{"id":30687,"date":"2023-07-16T08:42:36","date_gmt":"2023-07-16T05:12:36","guid":{"rendered":"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/"},"modified":"2023-07-16T08:42:36","modified_gmt":"2023-07-16T05:12:36","slug":"demystifying-array-methods-2bml","status":"publish","type":"post","link":"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/","title":{"rendered":"\u0631\u0645\u0632\u06af\u0634\u0627\u06cc\u06cc \u0631\u0648\u0634 \u0647\u0627\u06cc \u0622\u0631\u0627\u06cc\u0647 &#8211; \u0627\u0646\u062c\u0645\u0646 DEV"},"content":{"rendered":"<div data-article-id=\"1538403\" id=\"article-body\">\n<p>\u0628\u0647 \u0646\u0648\u0639\u06cc\u060c \u0628\u0647 \u0646\u0648\u0639\u06cc\u060c \u0645\u0631\u062f\u0645 \u0641\u06a9\u0631 \u0645\u06cc \u06a9\u0646\u0646\u062f <code>for<\/code> \u062f\u0631\u06a9 \u0648 \u062f\u0631\u06a9 \u062d\u0644\u0642\u0647 \u0647\u0627 \u0622\u0633\u0627\u0646 \u062a\u0631 \u0627\u0633\u062a&#8230; \u0645\u0646 \u0627\u06cc\u0646\u062c\u0627 \u0647\u0633\u062a\u0645 \u062a\u0627 \u0622\u0646 \u0631\u0627 \u062a\u063a\u06cc\u06cc\u0631 \u062f\u0647\u0645.<\/p>\n<p>\u0645\u0646 \u0627\u0632 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u062e\u0648\u0627\u0647\u0645 \u06a9\u0631\u062f\u060c \u0627\u0645\u0627 \u0628\u06cc\u0634\u062a\u0631 \u0632\u0628\u0627\u0646\u200c\u0647\u0627 \u0631\u0648\u0634\u200c\u0647\u0627 \u0631\u0627 \u0628\u0647 \u0631\u0648\u0634\u06cc \u062f\u06cc\u06af\u0631 \u067e\u06cc\u0627\u062f\u0647\u200c\u0633\u0627\u0632\u06cc \u0645\u06cc\u200c\u06a9\u0646\u0646\u062f\u060c \u06af\u0627\u0647\u06cc \u0627\u0648\u0642\u0627\u062a \u0628\u0627 \u06a9\u0645\u06cc \u062a\u0641\u0627\u0648\u062a \u062f\u0631 \u0646\u0627\u0645\u200c\u06af\u0630\u0627\u0631\u06cc.<\/p>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter-rtl ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">\u0641\u0647\u0631\u0633\u062a \u0645\u0637\u0627\u0644\u0628<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"\u062a\u063a\u06cc\u06cc\u0631 \u0648\u0636\u0639\u06cc\u062a \u0641\u0647\u0631\u0633\u062a \u0645\u0637\u0627\u0644\u0628\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/#%D9%85%D8%A8%D8%A7%D9%86%DB%8C\" >\u0645\u0628\u0627\u0646\u06cc<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/#%D8%AF%D9%88_%DA%86%DB%8C%D8%B2_%D8%B1%D8%A7_%D8%A8%D8%A7%DB%8C%D8%AF_%D8%A8%D9%87_%D8%AE%D8%A7%D8%B7%D8%B1_%D8%A8%D8%B3%D9%BE%D8%A7%D8%B1%DB%8C%D8%AF\" >\u062f\u0648 \u0686\u06cc\u0632 \u0631\u0627 \u0628\u0627\u06cc\u062f \u0628\u0647 \u062e\u0627\u0637\u0631 \u0628\u0633\u067e\u0627\u0631\u06cc\u062f:<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/#%D8%A8%D8%B1%D8%A7%DB%8C_%D9%87%D8%B1\" >\u0628\u0631\u0627\u06cc \u0647\u0631<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/#%D9%86%D9%82%D8%B4%D9%87\" >\u0646\u0642\u0634\u0647<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/#%D9%83%D8%A7%D9%87%D8%B4_%D8%AF%D8%A7%D8%AF%D9%86\" >\u0643\u0627\u0647\u0634 \u062f\u0627\u062f\u0646<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/#%D9%81%DB%8C%D9%84%D8%AA%D8%B1_%DA%A9%D9%86%DB%8C%D8%AF\" >\u0641\u06cc\u0644\u062a\u0631 \u06a9\u0646\u06cc\u062f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/#%D9%85%D8%B3%D8%B7%D8%AD_%D9%88_%D9%85%D8%B3%D8%B7%D8%AD_%D9%86%D9%82%D8%B4%D9%87\" >\u0645\u0633\u0637\u062d \u0648 \u0645\u0633\u0637\u062d \u0646\u0642\u0634\u0647<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/#%D8%A8%D8%B1%D8%AE%DB%8C_%D9%88_%D9%87%D8%B1\" >\u0628\u0631\u062e\u06cc \u0648 \u0647\u0631<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/#%D9%BE%DB%8C%D8%AF%D8%A7_%DA%A9%D8%B1%D8%AF%D9%86_%D9%88_%D9%BE%DB%8C%D8%AF%D8%A7_%DA%A9%D8%B1%D8%AF%D9%86_%D8%A7%DB%8C%D9%86%D8%AF%DA%A9%D8%B3\" >\u067e\u06cc\u062f\u0627 \u06a9\u0631\u062f\u0646 \u0648 \u067e\u06cc\u062f\u0627 \u06a9\u0631\u062f\u0646 \u0627\u06cc\u0646\u062f\u06a9\u0633<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/#%D8%B4%D8%A7%D9%85%D9%84_%D9%85%DB%8C_%D8%B4%D9%88%D8%AF\" >\u0634\u0627\u0645\u0644 \u0645\u06cc \u0634\u0648\u062f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/nabfollower.com\/blog\/demystifying-array-methods-2bml\/#%D8%A2%D8%AE%D8%B1%DB%8C%D9%86_%D8%A7%D8%B8%D9%87%D8%A7%D8%B1%D8%A7%D8%AA\" >\u0622\u062e\u0631\u06cc\u0646 \u0627\u0638\u0647\u0627\u0631\u0627\u062a<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"%D9%85%D8%A8%D8%A7%D9%86%DB%8C\"><\/span>\n<p>  \u0645\u0628\u0627\u0646\u06cc<br \/>\n<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0627\u06a9\u062b\u0631 \u0631\u0648\u0634 \u0647\u0627\u060c \u0628\u0647 \u0627\u0633\u062a\u062b\u0646\u0627\u06cc \u0645\u0648\u0627\u0631\u062f\u060c \u062f\u0627\u0631\u0627\u06cc \u0627\u0645\u0636\u0627\u06cc \u06cc\u06a9\u0633\u0627\u0646 \u0647\u0633\u062a\u0646\u062f.<\/p>\n<p>\u0628\u06cc\u0627\u06cc\u06cc\u062f \u0628\u0627 \u0622\u0646 \u0645\u0642\u0627\u06cc\u0633\u0647 \u06a9\u0646\u06cc\u0645 <code>for<\/code> \u062d\u0644\u0642\u0647 \u0647\u0627:<\/p>\n<div class=\"highlight js-code-highlight\">\n<pre class=\"highlight javascript\"><code><span class=\"kd\">const<\/span> <span class=\"nx\">array<\/span> <span class=\"o\">=<\/span> <span class=\"p\">[<\/span><span class=\"dl\">'<\/span><span class=\"s1\">a<\/span><span class=\"dl\">'<\/span><span class=\"p\">,<\/span> <span class=\"dl\">'<\/span><span class=\"s1\">b<\/span><span class=\"dl\">'<\/span><span class=\"p\">,<\/span> <span class=\"dl\">'<\/span><span class=\"s1\">c<\/span><span class=\"dl\">'<\/span><span class=\"p\">];<\/span>\n\n<span class=\"c1\">\/\/ the classic `for` loop you can have better<\/span>\n<span class=\"c1\">\/\/ control over the indexed you're using<\/span>\n<span class=\"k\">for<\/span> <span class=\"p\">(<\/span><span class=\"kd\">let<\/span> <span class=\"nx\">index<\/span> <span class=\"o\">=<\/span> <span class=\"mi\">0<\/span><span class=\"p\">;<\/span> <span class=\"nx\">index<\/span> <span class=\"o\">&lt;<\/span> <span class=\"nx\">array<\/span><span class=\"p\">.<\/span><span class=\"nx\">length<\/span><span class=\"p\">;<\/span> <span class=\"nx\">index<\/span><span class=\"o\">++<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\n  <span class=\"kd\">const<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">=<\/span> <span class=\"nx\">array<\/span><span class=\"p\">[<\/span><span class=\"nx\">index<\/span><span class=\"p\">];<\/span>\n  <span class=\"nx\">console<\/span><span class=\"p\">.<\/span><span class=\"nx\">log<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ a, b, c<\/span>\n<span class=\"p\">}<\/span>\n\n<span class=\"c1\">\/\/ the `for in` gives the index<\/span>\n<span class=\"k\">for<\/span> <span class=\"p\">(<\/span><span class=\"kd\">const<\/span> <span class=\"nx\">index<\/span> <span class=\"k\">in<\/span> <span class=\"nx\">array<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\n  <span class=\"kd\">const<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">=<\/span> <span class=\"nx\">array<\/span><span class=\"p\">[<\/span><span class=\"nx\">index<\/span><span class=\"p\">];<\/span>\n  <span class=\"nx\">console<\/span><span class=\"p\">.<\/span><span class=\"nx\">log<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ a, b, c<\/span>\n<span class=\"p\">}<\/span>\n\n<span class=\"c1\">\/\/ the `for of` gives the element<\/span>\n<span class=\"k\">for<\/span> <span class=\"p\">(<\/span><span class=\"kd\">const<\/span> <span class=\"nx\">element<\/span> <span class=\"k\">of<\/span> <span class=\"nx\">array<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\n  <span class=\"nx\">console<\/span><span class=\"p\">.<\/span><span class=\"nx\">log<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ a, b, c<\/span>\n<span class=\"p\">}<\/span>\n<\/code><\/pre>\n<div class=\"highlight__panel js-actions-panel\">\n<div class=\"highlight__panel-action js-fullscreen-code-action\">\n    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-on\"><title>\u0648\u0627\u0631\u062f \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M16 3h6v6h-2V5h-4V3zM2 3h6v2H4v4H2V3zm18 16v-4h2v6h-6v-2h4zM4 19h4v2H2v-6h2v4z\"\/>\n<\/svg><\/p>\n<p>    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-off\"><title>\u0627\u0632 \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u062e\u0627\u0631\u062c \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M18 7h4v2h-6V3h2v4zM8 9H2V7h4V3h2v6zm10 8v4h-2v-6h6v2h-4zM8 15v6H6v-4H2v-2h6z\"\/>\n<\/svg><\/p>\n<\/div>\n<\/div>\n<\/div>\n<ul>\n<li>\u0639\u0646\u0635\u0631 &#8211; \u0645\u0639\u0645\u0648\u0644\u0627\u064b \u0627\u06cc\u0646 \u062a\u0646\u0647\u0627 \u0686\u06cc\u0632\u06cc \u0627\u0633\u062a \u06a9\u0647 \u0648\u0627\u0642\u0639\u0627\u064b \u0646\u06cc\u0627\u0632 \u062f\u0627\u0631\u06cc\u062f<\/li>\n<li>index &#8211; \u06a9\u0627\u0631\u0628\u0631\u062f\u0647\u0627\u06cc\u06cc \u0628\u0631\u0627\u06cc \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u0627\u06cc\u0646\u062f\u06a9\u0633 \u0648\u062c\u0648\u062f \u062f\u0627\u0631\u062f<\/li>\n<li>\u0622\u0631\u0627\u06cc\u0647 &#8211; \u0647\u0646\u06af\u0627\u0645 \u0632\u0646\u062c\u06cc\u0631 \u06a9\u0631\u062f\u0646 \u0645\u062a\u062f\u0647\u0627\u060c \u0627\u06cc\u0646 \u0628\u0647 \u0634\u0645\u0627 \u0627\u0645\u06a9\u0627\u0646 \u0645\u06cc \u062f\u0647\u062f \u0627\u0632 \u0645\u0642\u0627\u062f\u06cc\u0631 \u0641\u0639\u0644\u06cc \u062f\u0631 \u0645\u0631\u062d\u0644\u0647 \u0627\u06cc \u06a9\u0647 \u062f\u0631 \u0622\u0646 \u0647\u0633\u062a\u06cc\u062f \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f.<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"%D8%AF%D9%88_%DA%86%DB%8C%D8%B2_%D8%B1%D8%A7_%D8%A8%D8%A7%DB%8C%D8%AF_%D8%A8%D9%87_%D8%AE%D8%A7%D8%B7%D8%B1_%D8%A8%D8%B3%D9%BE%D8%A7%D8%B1%DB%8C%D8%AF\"><\/span>\n<p>  \u062f\u0648 \u0686\u06cc\u0632 \u0631\u0627 \u0628\u0627\u06cc\u062f \u0628\u0647 \u062e\u0627\u0637\u0631 \u0628\u0633\u067e\u0627\u0631\u06cc\u062f:<br \/>\n<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li>\u0627\u0632 \u0628\u0647\u062a\u0631\u06cc\u0646 \u0631\u0648\u0634 \u0628\u0631\u0627\u06cc \u06a9\u0627\u0631\u06cc \u06a9\u0647 \u0627\u0646\u062c\u0627\u0645 \u0645\u06cc \u062f\u0647\u06cc\u062f \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f<\/li>\n<\/ul>\n<p>\u0627\u06af\u0631 \u0646\u06cc\u0627\u0632\u06cc \u0628\u0647 \u0628\u0627\u0632\u06af\u0631\u062f\u0627\u0646\u062f\u0646 \u0686\u06cc\u0632\u06cc \u0646\u062f\u0627\u0631\u06cc\u062f\u060c \u0627\u0632 a <code>map<\/code> \u0627\u06cc\u0646 \u0628\u0627\u0632\u06af\u0634\u062a \u0628\u0627\u0639\u062b \u0645\u06cc \u0634\u0648\u062f \u0641\u06a9\u0631 \u06a9\u0646\u0645 \u0634\u0645\u0627 \u0641\u0631\u0627\u0645\u0648\u0634 \u06a9\u0631\u062f\u0647 \u0627\u06cc\u062f \u0686\u06cc\u0632\u06cc \u0631\u0627 \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u06cc\u062f. <\/p>\n<p>\u0628\u0647 \u0647\u0645\u06cc\u0646 \u062a\u0631\u062a\u06cc\u0628\u060c \u0631\u0627\u0647\u200c\u0647\u0627\u06cc \u062f\u0648\u0631\u0628\u0631\u06af\u0631\u062f\u0627\u0646 \u0632\u06cc\u0627\u062f\u06cc \u0648\u062c\u0648\u062f \u062f\u0627\u0631\u062f \u06a9\u0647 \u0648\u0636\u0639\u06cc\u062a \u0641\u0639\u0644\u06cc \u0632\u0628\u0627\u0646 \u0631\u0627\u0647\u200c\u0647\u0627\u06cc \u0628\u0647\u062a\u0631\u06cc \u0628\u0631\u0627\u06cc \u0627\u0646\u062c\u0627\u0645 \u0622\u0646\u200c\u0647\u0627 \u062f\u0627\u0631\u062f\u060c \u0645\u0627\u0646\u0646\u062f \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 <code>findIndex !== -1<\/code> \u0648\u0642\u062a\u06cc \u06cc\u06a9 <code>some<\/code> \u0647\u0645\u06cc\u0646 \u06a9\u0627\u0631 \u0631\u0627 \u062e\u0648\u0627\u0647\u062f \u06a9\u0631\u062f.<\/p>\n<p>\u062a\u0627 \u0632\u0645\u0627\u0646\u06cc \u06a9\u0647 \u0686\u06cc\u0632\u06cc \u06a9\u0647 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u06cc\u062f \u0622\u0631\u0627\u06cc\u0647 \u062f\u06cc\u06af\u0631\u06cc \u0628\u0627\u0634\u062f\u060c \u0645\u06cc \u062a\u0648\u0627\u0646\u06cc\u062f \u06a9\u0627\u0631\u06cc \u0627\u0646\u062c\u0627\u0645 \u062f\u0647\u06cc\u062f \u0648 \u0622\u0646 \u0631\u0627 \u0628\u0647 \u0645\u0631\u062d\u0644\u0647 \u0628\u0639\u062f\u06cc \u0645\u0646\u062a\u0642\u0644 \u06a9\u0646\u06cc\u062f. <\/p>\n<p>\u06af\u0627\u0647\u06cc \u0627\u0648\u0642\u0627\u062a \u0627\u06cc\u0646 \u0645\u0646\u0637\u0642\u06cc \u0627\u0633\u062a\u060c \u0627\u0645\u0627 \u06af\u0627\u0647\u06cc \u0627\u0648\u0642\u0627\u062a\u060c \u0645\u0645\u06a9\u0646 \u0627\u0633\u062a \u0628\u062e\u0648\u0627\u0647\u06cc\u062f \u0622\u0646\u0647\u0627 \u0631\u0627 \u0628\u0647 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc \u062a\u0648\u0635\u06cc\u0641\u06cc \u0627\u062e\u062a\u0635\u0627\u0635 \u062f\u0647\u06cc\u062f.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%D8%A8%D8%B1%D8%A7%DB%8C_%D9%87%D8%B1\"><\/span>\n<p>  \u0628\u0631\u0627\u06cc \u0647\u0631<br \/>\n<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>&#8220;\u0628\u0631\u0627\u06cc \u0647\u0631 \u0639\u0646\u0635\u0631&#8221; \u062f\u0631 \u0622\u0631\u0627\u06cc\u0647\u060c \u06a9\u0627\u0631\u06cc \u0627\u0646\u062c\u0627\u0645 \u0645\u06cc \u062f\u0647\u062f \u0648 \u0686\u06cc\u0632\u06cc \u0628\u0631 \u0646\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f.<\/p>\n<div class=\"highlight js-code-highlight\">\n<pre class=\"highlight javascript\"><code><span class=\"p\">[<\/span><span class=\"dl\">'<\/span><span class=\"s1\">a<\/span><span class=\"dl\">'<\/span><span class=\"p\">,<\/span> <span class=\"dl\">'<\/span><span class=\"s1\">b<\/span><span class=\"dl\">'<\/span><span class=\"p\">,<\/span> <span class=\"dl\">'<\/span><span class=\"s1\">c<\/span><span class=\"dl\">'<\/span><span class=\"p\">].<\/span><span class=\"nx\">forEach<\/span><span class=\"p\">((<\/span><span class=\"nx\">element<\/span><span class=\"p\">)<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"p\">{<\/span>\n  <span class=\"c1\">\/\/ console.log doesn't return anything<\/span>\n  <span class=\"c1\">\/\/ so it's perfect for the forEach<\/span>\n  <span class=\"nx\">console<\/span><span class=\"p\">.<\/span><span class=\"nx\">log<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ a, b, c<\/span>\n<span class=\"p\">})<\/span>\n<\/code><\/pre>\n<div class=\"highlight__panel js-actions-panel\">\n<div class=\"highlight__panel-action js-fullscreen-code-action\">\n    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-on\"><title>\u0648\u0627\u0631\u062f \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M16 3h6v6h-2V5h-4V3zM2 3h6v2H4v4H2V3zm18 16v-4h2v6h-6v-2h4zM4 19h4v2H2v-6h2v4z\"\/>\n<\/svg><\/p>\n<p>    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-off\"><title>\u0627\u0632 \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u062e\u0627\u0631\u062c \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M18 7h4v2h-6V3h2v4zM8 9H2V7h4V3h2v6zm10 8v4h-2v-6h6v2h-4zM8 15v6H6v-4H2v-2h6z\"\/>\n<\/svg><\/p>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0634\u0645\u0627 \u0632\u0645\u0627\u0646\u06cc \u0627\u0632 \u0622\u0646 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0645\u06cc \u06a9\u0646\u06cc\u062f \u06a9\u0647 \u0641\u0642\u0637 \u0646\u06cc\u0627\u0632 \u0628\u0647 \u0627\u0646\u062c\u0627\u0645 \u06a9\u0627\u0631\u06cc \u062f\u0627\u0631\u06cc\u062f \u0648 \u0686\u06cc\u0632\u06cc \u0631\u0627 \u067e\u0633 \u0646\u0645\u06cc \u062f\u0647\u06cc\u062f: \u0633\u06cc\u0627\u0647\u0647 \u0647\u0627\u060c \u0646\u0627\u0646 \u062a\u0633\u062a\u2026<\/p>\n<p>\u062f\u0631\u06a9 \u0648 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u0622\u0646 \u0622\u0633\u0627\u0646 \u0627\u0633\u062a\u060c \u0627\u0645\u0627 \u0627\u0632 \u0622\u0646\u062c\u0627\u06cc\u06cc \u06a9\u0647 \u0686\u06cc\u0632\u06cc \u0631\u0627 \u0628\u0631 \u0646\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f\u060c \u0648\u0627\u0642\u0639\u0627\u064b \u06a9\u0627\u0631\u0628\u0631\u062f\u0647\u0627\u06cc \u0632\u06cc\u0627\u062f\u06cc \u0648\u062c\u0648\u062f \u0646\u062f\u0627\u0631\u062f.  (\u0631\u0648\u0634 \u0647\u0627\u06cc \u0628\u0647\u062a\u0631\u06cc \u0628\u0631\u0627\u06cc \u0647\u0631 \u0686\u06cc\u0632\u06cc \u06a9\u0647 \u0641\u06a9\u0631 \u0645\u06cc \u06a9\u0646\u06cc\u062f \u0648\u062c\u0648\u062f \u062f\u0627\u0631\u062f)<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%D9%86%D9%82%D8%B4%D9%87\"><\/span>\n<p>  \u0646\u0642\u0634\u0647<br \/>\n<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0641\u0631\u0632\u0646\u062f \u067e\u0648\u0633\u062a\u0631 \u0645\u062a\u062f\u0647\u0627\u06cc \u0622\u0631\u0627\u06cc\u0647!<\/p>\n<p>\u0628\u0631\u0627\u06cc \u0647\u0631 \u0639\u0646\u0635\u0631 \u062f\u0631 \u0622\u0631\u0627\u06cc\u0647\u060c \u06cc\u06a9 \u0645\u0642\u062f\u0627\u0631 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f.<\/p>\n<p>(\u062a\u0648\u062c\u0647: \u062d\u062a\u06cc \u0627\u06af\u0631 \u0628\u0631\u0646\u06af\u0631\u062f\u06cc\u062f \u0628\u0627\u0632 \u0645\u06cc \u06af\u0631\u062f\u062f <code>undefined<\/code>)<\/p>\n<div class=\"highlight js-code-highlight\">\n<pre class=\"highlight javascript\"><code><span class=\"c1\">\/\/ not adding {} in the arrow function, means it returns implicitly<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">map<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">*<\/span> <span class=\"mi\">2<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ result array is [2, 4, 6]<\/span>\n\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">map<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"p\">{<\/span>\n  <span class=\"k\">if<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">!==<\/span> <span class=\"mi\">0<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span> <span class=\"c1\">\/\/ remainder of the division by 2 not equal to zero <\/span>\n    <span class=\"k\">return<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">*<\/span> <span class=\"mi\">2<\/span><span class=\"p\">;<\/span>\n  <span class=\"p\">}<\/span>\n  <span class=\"c1\">\/\/ no \"else\" returns<\/span>\n<span class=\"p\">})<\/span> <span class=\"c1\">\/\/ resulting array [2, undefined, 6]<\/span>\n<\/code><\/pre>\n<div class=\"highlight__panel js-actions-panel\">\n<div class=\"highlight__panel-action js-fullscreen-code-action\">\n    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-on\"><title>\u0648\u0627\u0631\u062f \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M16 3h6v6h-2V5h-4V3zM2 3h6v2H4v4H2V3zm18 16v-4h2v6h-6v-2h4zM4 19h4v2H2v-6h2v4z\"\/>\n<\/svg><\/p>\n<p>    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-off\"><title>\u0627\u0632 \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u062e\u0627\u0631\u062c \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M18 7h4v2h-6V3h2v4zM8 9H2V7h4V3h2v6zm10 8v4h-2v-6h6v2h-4zM8 15v6H6v-4H2v-2h6z\"\/>\n<\/svg><\/p>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0627\u0632 \u0622\u0646\u062c\u0627\u06cc\u06cc \u06a9\u0647 \u0622\u0631\u0627\u06cc\u0647 \u0627\u06cc \u0628\u0627 \u0647\u0645\u0627\u0646 \u0627\u0646\u062f\u0627\u0632\u0647 \u0631\u0627 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f\u060c \u0645\u06cc \u062a\u0648\u0627\u0646 \u0627\u0632 \u0622\u0646 \u0628\u0631\u0627\u06cc \u0686\u0646\u062f\u06cc\u0646 \u0686\u06cc\u0632 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0631\u062f \u0648 \u0632\u0646\u062c\u06cc\u0631\u0647 \u0633\u0627\u0632\u06cc \u0631\u0627 \u0622\u0633\u0627\u0646 \u0645\u06cc \u06a9\u0646\u062f. <\/p>\n<h2><span class=\"ez-toc-section\" id=\"%D9%83%D8%A7%D9%87%D8%B4_%D8%AF%D8%A7%D8%AF%D9%86\"><\/span>\n<p>  \u0643\u0627\u0647\u0634 \u062f\u0627\u062f\u0646<br \/>\n<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0622\u0641\u062a \u0645\u0631\u062f\u0645\u06cc \u06a9\u0647 \u0631\u0648\u0634\u200c\u0647\u0627 \u0631\u0627 \u06cc\u0627\u062f \u0645\u06cc\u200c\u06af\u06cc\u0631\u0646\u062f&#8230; \u0627\u0645\u0627 \u0648\u0627\u0642\u0639\u0627\u064b \u0622\u0646\u0642\u062f\u0631\u0647\u0627 \u0647\u0645 \u067e\u06cc\u0686\u06cc\u062f\u0647 \u0646\u06cc\u0633\u062a.<\/p>\n<p>\u0628\u0631\u0627\u06cc \u0647\u0631 \u0639\u0646\u0635\u0631 \u062f\u0631 \u0622\u0631\u0627\u06cc\u0647\u060c &#8220;\u06cc\u06a9&#8221; \u0686\u06cc\u0632 \u0631\u0627 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f (\u06a9\u0647 \u0645\u06cc \u062a\u0648\u0627\u0646\u062f \u0647\u0631 \u0686\u06cc\u0632\u06cc \u0628\u0627\u0634\u062f). <\/p>\n<p>\u0628\u0647 \u0635\u0648\u0631\u062a \u0627\u062e\u062a\u06cc\u0627\u0631\u06cc\u060c \u0645\u06cc \u062a\u0648\u0627\u0646\u06cc\u062f \u06cc\u06a9 \u0645\u0642\u062f\u0627\u0631 \u0634\u0631\u0648\u0639 \u062f\u0627\u0634\u062a\u0647 \u0628\u0627\u0634\u06cc\u062f.<\/p>\n<div class=\"highlight js-code-highlight\">\n<pre class=\"highlight javascript\"><code><span class=\"c1\">\/\/ classical use case<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">reduce<\/span><span class=\"p\">((<\/span><span class=\"nx\">accumulator<\/span><span class=\"p\">,<\/span> <span class=\"nx\">element<\/span><span class=\"p\">)<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"nx\">accumulator<\/span> <span class=\"o\">+<\/span> <span class=\"nx\">element<\/span><span class=\"p\">,<\/span> <span class=\"mi\">0<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ returns 6<\/span>\n\n<span class=\"c1\">\/\/ classical mistake nr 1: not returning anything<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">reduce<\/span><span class=\"p\">((<\/span><span class=\"nx\">accumulator<\/span><span class=\"p\">,<\/span> <span class=\"nx\">element<\/span><span class=\"p\">)<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"p\">{<\/span>\n  <span class=\"nx\">console<\/span><span class=\"p\">.<\/span><span class=\"nx\">log<\/span><span class=\"p\">(<\/span><span class=\"nx\">accumulator<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ 0 (initial value), undefined, undefined (undefined because you didn't return)<\/span>\n  <span class=\"nx\">console<\/span><span class=\"p\">.<\/span><span class=\"nx\">log<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ 1, 2, 3<\/span>\n  <span class=\"nx\">accumulator<\/span> <span class=\"o\">+<\/span> <span class=\"nx\">element<\/span><span class=\"p\">;<\/span> <span class=\"c1\">\/\/ this would be 1 (0 + 1), then NaN, NaN (number + undefined\/NaN)<\/span>\n  <span class=\"c1\">\/\/ always remember to return something, even if only the accumulator<\/span>\n<span class=\"p\">},<\/span> <span class=\"mi\">0<\/span><span class=\"p\">);<\/span>\n\n<span class=\"c1\">\/\/ (possible) mistake: not having an initial value<\/span>\n<span class=\"c1\">\/\/ no initial value means the first element is the initial value<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">reduce<\/span><span class=\"p\">((<\/span><span class=\"nx\">accumulator<\/span><span class=\"p\">,<\/span> <span class=\"nx\">element<\/span><span class=\"p\">)<\/span><span class=\"o\">=&gt;<\/span> <span class=\"nx\">accumulator<\/span> <span class=\"o\">+<\/span> <span class=\"nx\">element<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ retuns 6<\/span>\n<span class=\"p\">[].<\/span><span class=\"nx\">reduce<\/span><span class=\"p\">((<\/span><span class=\"nx\">accumulator<\/span><span class=\"p\">,<\/span> <span class=\"nx\">element<\/span><span class=\"p\">)<\/span><span class=\"o\">=&gt;<\/span> <span class=\"nx\">accumulator<\/span> <span class=\"o\">+<\/span> <span class=\"nx\">element<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ throws because empty array with no initial value<\/span>\n\n<span class=\"c1\">\/\/ things start to be different for more complex use cases<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">reduce<\/span><span class=\"p\">((<\/span><span class=\"nx\">accumulator<\/span><span class=\"p\">,<\/span> <span class=\"nx\">element<\/span><span class=\"p\">)<\/span><span class=\"o\">=&gt;<\/span><span class=\"p\">{<\/span>\n  <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">===<\/span> <span class=\"mi\">0<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\n    <span class=\"nx\">accumulator<\/span><span class=\"p\">.<\/span><span class=\"nx\">even<\/span><span class=\"p\">.<\/span><span class=\"nx\">push<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span><span class=\"p\">);<\/span>\n  <span class=\"p\">}<\/span> <span class=\"k\">else<\/span> <span class=\"p\">{<\/span>\n    <span class=\"nx\">accumulator<\/span><span class=\"p\">.<\/span><span class=\"nx\">odd<\/span><span class=\"p\">.<\/span><span class=\"nx\">push<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span><span class=\"p\">);<\/span>\n  <span class=\"p\">}<\/span>\n\n  <span class=\"k\">return<\/span> <span class=\"nx\">accumulator<\/span><span class=\"p\">;<\/span>\n<span class=\"c1\">\/\/ below I'm using JSDoc to type the initial value<\/span>\n<span class=\"c1\">\/\/ because using JS doesn't mean not using types ;]<\/span>\n<span class=\"p\">},<\/span> <span class=\"cm\">\/** @type {{ even: number[], odd: number[] }} *\/<\/span> <span class=\"p\">({<\/span> <span class=\"na\">even<\/span><span class=\"p\">:<\/span> <span class=\"p\">[],<\/span> <span class=\"na\">odd<\/span><span class=\"p\">:<\/span> <span class=\"p\">[]}));<\/span>\n<span class=\"c1\">\/\/ this returns: { even: [ 2 ], odd: [ 1, 3 ] }<\/span>\n<span class=\"c1\">\/\/ Not using an initial value will break this in multiple ways.<\/span>\n\n<span class=\"c1\">\/\/ this is another way to write the same thing<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">reduce<\/span><span class=\"p\">((<\/span><span class=\"nx\">accumulator<\/span><span class=\"p\">,<\/span> <span class=\"nx\">element<\/span><span class=\"p\">)<\/span><span class=\"o\">=&gt;<\/span><span class=\"p\">{<\/span>\n  <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">===<\/span> <span class=\"mi\">0<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\n    <span class=\"k\">return<\/span> <span class=\"p\">{<\/span>\n      <span class=\"p\">...<\/span><span class=\"nx\">accumulator<\/span><span class=\"p\">,<\/span>\n      <span class=\"na\">even<\/span><span class=\"p\">:<\/span> <span class=\"nx\">accumulator<\/span><span class=\"p\">.<\/span><span class=\"nx\">even<\/span><span class=\"p\">.<\/span><span class=\"nx\">concat<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span><span class=\"p\">),<\/span>\n    <span class=\"p\">}<\/span>\n  <span class=\"p\">}<\/span>\n\n  <span class=\"k\">return<\/span> <span class=\"p\">{<\/span>\n    <span class=\"p\">...<\/span><span class=\"nx\">accumulator<\/span><span class=\"p\">,<\/span>\n    <span class=\"na\">odd<\/span><span class=\"p\">:<\/span> <span class=\"nx\">accumulator<\/span><span class=\"p\">.<\/span><span class=\"nx\">odd<\/span><span class=\"p\">.<\/span><span class=\"nx\">concat<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span><span class=\"p\">),<\/span>\n  <span class=\"p\">}<\/span>\n<span class=\"p\">},<\/span> <span class=\"cm\">\/** @type {{ even: number[], odd: number[] }} *\/<\/span><span class=\"p\">({<\/span> <span class=\"na\">even<\/span><span class=\"p\">:<\/span> <span class=\"p\">[],<\/span> <span class=\"na\">odd<\/span><span class=\"p\">:<\/span> <span class=\"p\">[]}));<\/span>\n<span class=\"c1\">\/\/ the important thing to remember is to always return something<\/span>\n\n<span class=\"c1\">\/\/ the \"one\" thing it returns can be anything:<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">reduce<\/span><span class=\"p\">((<\/span><span class=\"nx\">accumulator<\/span><span class=\"p\">,<\/span> <span class=\"nx\">element<\/span><span class=\"p\">)<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"p\">{<\/span>\n  <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">===<\/span> <span class=\"mi\">0<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\n    <span class=\"nx\">accumulator<\/span><span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">]<\/span> <span class=\"o\">+=<\/span> <span class=\"nx\">element<\/span><span class=\"p\">;<\/span>\n  <span class=\"p\">}<\/span> <span class=\"k\">else<\/span> <span class=\"p\">{<\/span>\n    <span class=\"nx\">accumulator<\/span><span class=\"p\">[<\/span><span class=\"mi\">0<\/span><span class=\"p\">]<\/span> <span class=\"o\">+=<\/span> <span class=\"nx\">element<\/span><span class=\"p\">;<\/span>\n  <span class=\"p\">}<\/span>\n  <span class=\"k\">return<\/span> <span class=\"nx\">accumulator<\/span><span class=\"p\">;<\/span>\n<span class=\"p\">},<\/span> <span class=\"cm\">\/** @type {[number, number]} [*\/<\/span><span class=\"p\">([<\/span><span class=\"mi\">0<\/span><span class=\"p\">,<\/span> <span class=\"mi\">0<\/span><span class=\"p\">]));<\/span>\n<span class=\"c1\">\/\/ this returns [4, 2]<\/span>\n<span class=\"c1\">\/\/ and would again have multiple problems without an initial value<\/span>\n<\/code><\/pre>\n<div class=\"highlight__panel js-actions-panel\">\n<div class=\"highlight__panel-action js-fullscreen-code-action\">\n    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-on\"><title>\u0648\u0627\u0631\u062f \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M16 3h6v6h-2V5h-4V3zM2 3h6v2H4v4H2V3zm18 16v-4h2v6h-6v-2h4zM4 19h4v2H2v-6h2v4z\"\/>\n<\/svg><\/p>\n<p>    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-off\"><title>\u0627\u0632 \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u062e\u0627\u0631\u062c \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M18 7h4v2h-6V3h2v4zM8 9H2V7h4V3h2v6zm10 8v4h-2v-6h6v2h-4zM8 15v6H6v-4H2v-2h6z\"\/>\n<\/svg><\/p>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0627\u06af\u0631 \u0645\u06cc\u200c\u062e\u0648\u0627\u0647\u06cc\u062f \u06cc\u06a9 \u06cc\u0627 \u0686\u0646\u062f \u0645\u062a\u063a\u06cc\u0631 \u0631\u0627 \u062f\u0631 \u062e\u0627\u0631\u062c \u0646\u0645\u0648\u0646\u0647\u200c\u0633\u0627\u0632\u06cc \u06a9\u0646\u06cc\u062f\u060c \u0627\u0632 a \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f <code>for<\/code> \u062d\u0644\u0642\u0647 \u06cc\u0627 \u062d\u062a\u06cc \u06cc\u06a9 <code>forEach<\/code> \u0648 \u0622\u0646 \u0631\u0627 \u062c\u0647\u0634 \u062f\u0647\u06cc\u062f\u060c \u0633\u067e\u0633 \u06cc\u06a9 \u0645\u0648\u0631\u062f \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0628\u0631\u0627\u06cc \u0622\u0646 \u0627\u0633\u062a <code>reduce<\/code>.<\/p>\n<p>\u0647\u0645\u06cc\u0634\u0647 \u06cc\u06a9 \u0686\u06cc\u0632 \u0631\u0627 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f\u060c \u0648 \u0647\u0645\u0627\u0646\u0637\u0648\u0631 \u06a9\u0647 \u0645\u06cc \u0628\u06cc\u0646\u06cc\u062f \u0645\u06cc \u062a\u0648\u0627\u0646\u062f \u0647\u0631 \u0686\u06cc\u0632\u06cc \u0628\u0627\u0634\u062f: \u0639\u062f\u062f\u060c \u0631\u0634\u062a\u0647\u060c \u0622\u0631\u0627\u06cc\u0647\u060c \u0634\u06cc\u2026<\/p>\n<p>\u062f\u0631 \u062d\u0627\u0644\u06cc \u06a9\u0647\u060c \u0634\u0645\u0627 \u0627\u0633\u0627\u0633\u0627\u064b \u0645\u06cc \u062a\u0648\u0627\u0646\u06cc\u062f \u0647\u0631 \u06a9\u0627\u0631\u06cc \u0631\u0627 \u0628\u0627 \u0622\u0646 \u0627\u0646\u062c\u0627\u0645 \u062f\u0647\u06cc\u062f <code>reduce<\/code>\u060c \u0628\u0631\u0631\u0633\u06cc \u06a9\u0646\u06cc\u062f \u06a9\u0647 \u0622\u06cc\u0627 \u0631\u0648\u0634 \u062f\u06cc\u06af\u0631\u06cc \u0648\u062c\u0648\u062f \u0646\u062f\u0627\u0631\u062f \u06a9\u0647 \u0627\u06cc\u0646 \u0645\u0648\u0631\u062f \u0631\u0627 \u0628\u0647\u062a\u0631 \u067e\u0648\u0634\u0634 \u062f\u0647\u062f.<\/p>\n<p>\u06cc\u06a9 \u0646\u06cc\u0632 \u0648\u062c\u0648\u062f \u062f\u0627\u0631\u062f <code>reduceRight<\/code> \u0627\u06cc\u0646 \u0647\u0645\u0627\u0646 \u0686\u06cc\u0632\u06cc \u0627\u0633\u062a\u060c \u0627\u0645\u0627 \u0627\u0632 \u0622\u062e\u0631\u06cc\u0646 \u0639\u0646\u0635\u0631 \u0634\u0631\u0648\u0639 \u0645\u06cc \u0634\u0648\u062f.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%D9%81%DB%8C%D9%84%D8%AA%D8%B1_%DA%A9%D9%86%DB%8C%D8%AF\"><\/span>\n<p>  \u0641\u06cc\u0644\u062a\u0631 \u06a9\u0646\u06cc\u062f<br \/>\n<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0628\u0631\u0627\u06cc \u0647\u0631 \u0639\u0646\u0635\u0631 \u062f\u0631 \u0622\u0631\u0627\u06cc\u0647\u060c \u0622\u0631\u0627\u06cc\u0647 \u0627\u06cc \u0631\u0627 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f \u06a9\u0647 \u0645\u06cc \u062a\u0648\u0627\u0646\u062f \u0627\u0646\u062f\u0627\u0632\u0647 \u06a9\u0648\u0686\u06a9\u062a\u0631\u06cc \u062f\u0627\u0634\u062a\u0647 \u0628\u0627\u0634\u062f.<\/p>\n<p>\u062f\u0631 \u062d\u0627\u0644\u06cc \u06a9\u0647 <code>reduce<\/code> \u06cc\u06a9 \u0686\u06cc\u0632 \u0631\u0627 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f\u060c <code>filter<\/code> \u0647\u0645\u06cc\u0634\u0647 \u0622\u0631\u0627\u06cc\u0647 \u0627\u06cc \u0631\u0627 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f \u06a9\u0647 \u0645\u06cc \u062a\u0648\u0627\u0646\u062f \u0627\u0632 \u062e\u0627\u0644\u06cc \u0628\u0647 \u0647\u0645\u0627\u0646 \u0627\u0646\u062f\u0627\u0632\u0647 \u0648\u0631\u0648\u062f\u06cc \u0628\u0627\u0634\u062f.<\/p>\n<div class=\"highlight js-code-highlight\">\n<pre class=\"highlight javascript\"><code><span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">filter<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">!==<\/span> <span class=\"mi\">0<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ returns [1, 3]<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">filter<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">5<\/span> <span class=\"o\">===<\/span> <span class=\"mi\">0<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ return [0]<\/span>\n\n<span class=\"c1\">\/\/ one common use case: remove falsy values<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">map<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"p\">{<\/span>\n  <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">!==<\/span> <span class=\"mi\">0<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\n    <span class=\"k\">return<\/span> <span class=\"nx\">element<\/span><span class=\"p\">;<\/span>\n  <span class=\"p\">}<\/span>\n<span class=\"p\">})<\/span> <span class=\"c1\">\/\/ at this point you would have: [1, undefined, 3]<\/span>\n  <span class=\"p\">.<\/span><span class=\"nx\">filter<\/span><span class=\"p\">(<\/span><span class=\"nb\">Boolean<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ after this return [1, 3]<\/span>\n<\/code><\/pre>\n<div class=\"highlight__panel js-actions-panel\">\n<div class=\"highlight__panel-action js-fullscreen-code-action\">\n    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-on\"><title>\u0648\u0627\u0631\u062f \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M16 3h6v6h-2V5h-4V3zM2 3h6v2H4v4H2V3zm18 16v-4h2v6h-6v-2h4zM4 19h4v2H2v-6h2v4z\"\/>\n<\/svg><\/p>\n<p>    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-off\"><title>\u0627\u0632 \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u062e\u0627\u0631\u062c \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M18 7h4v2h-6V3h2v4zM8 9H2V7h4V3h2v6zm10 8v4h-2v-6h6v2h-4zM8 15v6H6v-4H2v-2h6z\"\/>\n<\/svg><\/p>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0627\u06af\u0631 \u0645\u06cc \u062e\u0648\u0627\u0647\u06cc\u062f \u0645\u0642\u0627\u062f\u06cc\u0631 \u0631\u0627 \u0627\u0632 \u06cc\u06a9 \u0622\u0631\u0627\u06cc\u0647 \u062d\u0630\u0641 \u06a9\u0646\u06cc\u062f\u060c <code>filter<\/code> \u0631\u0648\u0634\u06cc \u0627\u0633\u062a \u06a9\u0647 \u0634\u0645\u0627 \u0645\u06cc \u062e\u0648\u0627\u0647\u06cc\u062f<\/p>\n<p>\u0648 \u0628\u0631\u0627\u06cc \u06a9\u0633\u0627\u0646\u06cc \u06a9\u0647 \u0646\u0645\u06cc \u062f\u0627\u0646\u0633\u062a\u0646\u062f: <code>filter(Boolean)<\/code> \u0631\u0648\u0634\u06cc \u0632\u06cc\u0628\u0627 \u0628\u0631\u0627\u06cc \u062d\u0630\u0641 \u0645\u0642\u0627\u062f\u06cc\u0631 \u0646\u0627\u062f\u0631\u0633\u062a \u0627\u0633\u062a.<\/p>\n<p>\u0628\u0627\u06cc\u062f \u0645\u0631\u0627\u0642\u0628 \u0628\u0627\u0634\u06cc\u062f \u06a9\u0647 \u0645\u0642\u0627\u062f\u06cc\u0631 \u0646\u0627\u062f\u0631\u0633\u062a \u0645\u0627\u0646\u0646\u062f \u0631\u0627 \u062d\u0630\u0641 \u06a9\u0646\u062f <code>''<\/code> (\u0631\u0634\u062a\u0647 \u062e\u0627\u0644\u06cc) \u0648 <code>0<\/code> (\u0635\u0641\u0631).<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%D9%85%D8%B3%D8%B7%D8%AD_%D9%88_%D9%85%D8%B3%D8%B7%D8%AD_%D9%86%D9%82%D8%B4%D9%87\"><\/span>\n<p>  \u0645\u0633\u0637\u062d \u0648 \u0645\u0633\u0637\u062d \u0646\u0642\u0634\u0647<br \/>\n<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0635\u0627\u0641 \u06a9\u0631\u062f\u0646 \u06cc\u06a9 \u0622\u0631\u0627\u06cc\u0647 \u0686\u06cc\u0632\u06cc \u0646\u06cc\u0633\u062a \u06a9\u0647 \u0647\u0631 \u0631\u0648\u0632 \u0627\u0632 \u0622\u0646 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f\u060c \u0627\u0645\u0627 \u0645\u0637\u0645\u0626\u0646\u0627\u064b \u062f\u0631 \u0628\u0633\u06cc\u0627\u0631\u06cc \u0627\u0632 \u0645\u0648\u0627\u0631\u062f \u0645\u0641\u06cc\u062f \u0627\u0633\u062a.  \u0627\u0633\u0627\u0633\u0627\u064b \u0628\u0647 <code>flat<\/code> \u062d\u0630\u0641 \u0627\u0628\u0639\u0627\u062f \u0627\u0632 \u06cc\u06a9 \u0622\u0631\u0627\u06cc\u0647 \u0627\u0633\u062a.<\/p>\n<p>\u0627\u06af\u0631 \u0645\u0627\u062a\u0631\u06cc\u0633 2&#215;2 \u062f\u0627\u0631\u06cc\u062f: <code>[[1, 1], [1, 1]]<\/code> \u0648 \u0634\u0645\u0627 \u0622\u0646 \u0631\u0627 \u0635\u0627\u0641 \u0645\u06cc \u06a9\u0646\u06cc\u062f\u060c \u062f\u0631 \u0646\u0647\u0627\u06cc\u062a \u0628\u0627 \u06cc\u06a9 \u0622\u0631\u0627\u06cc\u0647 4 \u0622\u06cc\u062a\u0645 \u0633\u0627\u062f\u0647 \u0645\u0648\u0627\u062c\u0647 \u0645\u06cc \u0634\u0648\u06cc\u062f: <code>[1, 1, 1, 1]<\/code>.<\/p>\n<div class=\"highlight js-code-highlight\">\n<pre class=\"highlight javascript\"><code><span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">map<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"p\">{<\/span>\n  <span class=\"k\">return<\/span> <span class=\"p\">[[[<\/span><span class=\"nx\">element<\/span><span class=\"p\">]]];<\/span> <span class=\"c1\">\/\/ sometimes you return values\/tuples<\/span>\n  <span class=\"c1\">\/\/ depending on what you really wanted to return, you just need to flat it<\/span>\n<span class=\"p\">})<\/span> <span class=\"c1\">\/\/ here would return [[[[1]]],[[[2]]],[[[3]]]]<\/span>\n  <span class=\"p\">.<\/span><span class=\"nx\">flat<\/span><span class=\"p\">(<\/span><span class=\"mi\">1<\/span><span class=\"p\">)<\/span> <span class=\"c1\">\/\/ returns [[[1]],[[2]],[[3]]]<\/span>\n  <span class=\"p\">.<\/span><span class=\"nx\">flat<\/span><span class=\"p\">(<\/span><span class=\"mi\">2<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ returns [1, 2, 3]<\/span>\n\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">map<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"p\">{<\/span>\n  <span class=\"k\">return<\/span> <span class=\"p\">[[[<\/span><span class=\"nx\">element<\/span><span class=\"p\">]]];<\/span>\n<span class=\"p\">})<\/span> <span class=\"c1\">\/\/ here would return [[[[1]]],[[[2]]],[[[3]]]]<\/span>\n  <span class=\"p\">.<\/span><span class=\"nx\">flat<\/span><span class=\"p\">(<\/span><span class=\"kc\">Infinity<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ returns [1, 2, 3]<\/span>\n  <span class=\"c1\">\/\/ flatting to infinity means it will remove all dimensions<\/span>\n<\/code><\/pre>\n<div class=\"highlight__panel js-actions-panel\">\n<div class=\"highlight__panel-action js-fullscreen-code-action\">\n    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-on\"><title>\u0648\u0627\u0631\u062f \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M16 3h6v6h-2V5h-4V3zM2 3h6v2H4v4H2V3zm18 16v-4h2v6h-6v-2h4zM4 19h4v2H2v-6h2v4z\"\/>\n<\/svg><\/p>\n<p>    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-off\"><title>\u0627\u0632 \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u062e\u0627\u0631\u062c \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M18 7h4v2h-6V3h2v4zM8 9H2V7h4V3h2v6zm10 8v4h-2v-6h6v2h-4zM8 15v6H6v-4H2v-2h6z\"\/>\n<\/svg><\/p>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0634\u0645\u0627 \u062a\u0645\u0627\u0633 \u0628\u06af\u06cc\u0631\u06cc\u062f <code>flat<\/code> \u0627\u0632 \u06cc\u06a9 \u0622\u0631\u0627\u06cc\u0647 \u0648 \u0639\u062f\u062f\u06cc \u0631\u0627 \u0645\u06cc \u06af\u06cc\u0631\u062f \u06a9\u0647 \u062a\u0639\u062f\u0627\u062f \u0627\u0628\u0639\u0627\u062f \u0631\u0627 \u0627\u0632 \u0622\u0646 \u062c\u062f\u0627 \u0645\u06cc \u06a9\u0646\u06cc\u062f.  \u0627\u06af\u0631 \u0645\u06cc \u062e\u0648\u0627\u0647\u06cc\u062f \u06cc\u06a9 \u0622\u0631\u0627\u06cc\u0647 \u0633\u0627\u062f\u0647 \u0628\u0647 \u0639\u0646\u0648\u0627\u0646 \u0646\u062a\u06cc\u062c\u0647 \u062f\u0627\u0634\u062a\u0647 \u0628\u0627\u0634\u06cc\u062f\u060c \u0645\u0647\u0645 \u0646\u06cc\u0633\u062a \u06a9\u0647 \u0622\u0631\u0627\u06cc\u0647 \u0686\u0642\u062f\u0631 \u0627\u0628\u0639\u0627\u062f \u062f\u0627\u0631\u062f\u060c \u0627\u0632 \u0622\u0646 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f <code>flat(Infinity)<\/code> \u0647\u0645\u0627\u0646\u0637\u0648\u0631 \u06a9\u0647 \u0627\u06cc\u0646 \u06a9\u0627\u0631 \u0631\u0627 \u0627\u0646\u062c\u0627\u0645 \u062e\u0648\u0627\u0647\u062f \u062f\u0627\u062f.<\/p>\n<div class=\"highlight js-code-highlight\">\n<pre class=\"highlight javascript\"><code><span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">flatMap<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"p\">{<\/span>\n  <span class=\"k\">return<\/span> <span class=\"p\">[<\/span><span class=\"nx\">element<\/span> <span class=\"o\">*<\/span> <span class=\"mi\">2<\/span><span class=\"p\">];<\/span> <span class=\"c1\">\/\/ returns [2], [4], [6]<\/span>\n<span class=\"p\">});<\/span> <span class=\"c1\">\/\/ returns [2, 4, 6] because it flattened<\/span>\n\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">flatMap<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"p\">{<\/span>\n  <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">===<\/span> <span class=\"mi\">0<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\n    <span class=\"k\">return<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">*<\/span> <span class=\"mi\">2<\/span><span class=\"p\">;<\/span> <span class=\"c1\">\/\/ return 4<\/span>\n  <span class=\"p\">}<\/span>\n  <span class=\"c1\">\/\/ without returning anything, it would result in [undefined, 4, undefined]<\/span>\n  <span class=\"c1\">\/\/ while flatMap doesn't remove falsy values<\/span>\n  <span class=\"c1\">\/\/ a flattened empty array disappear<\/span>\n  <span class=\"k\">return<\/span> <span class=\"p\">[];<\/span>\n<span class=\"p\">});<\/span> <span class=\"c1\">\/\/ returns [4]<\/span>\n<\/code><\/pre>\n<div class=\"highlight__panel js-actions-panel\">\n<div class=\"highlight__panel-action js-fullscreen-code-action\">\n    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-on\"><title>\u0648\u0627\u0631\u062f \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M16 3h6v6h-2V5h-4V3zM2 3h6v2H4v4H2V3zm18 16v-4h2v6h-6v-2h4zM4 19h4v2H2v-6h2v4z\"\/>\n<\/svg><\/p>\n<p>    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-off\"><title>\u0627\u0632 \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u062e\u0627\u0631\u062c \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M18 7h4v2h-6V3h2v4zM8 9H2V7h4V3h2v6zm10 8v4h-2v-6h6v2h-4zM8 15v6H6v-4H2v-2h6z\"\/>\n<\/svg><\/p>\n<\/div>\n<\/div>\n<\/div>\n<p><code>flatMap<\/code>  \u0627\u0633\u0627\u0633\u0627 \u06cc\u06a9 \u0627\u0633\u062a <code>map<\/code> \u0628\u0647 \u062f\u0646\u0628\u0627\u0644 <code>flat(1)<\/code>.<\/p>\n<p>TIL: \u0645\u06cc \u062a\u0648\u0627\u0646\u06cc\u062f \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f <code>flatMap<\/code> \u0648 \u0628\u0631\u06af\u0634\u062a <code>[]<\/code> \u0628\u0631\u0627\u06cc \u0645\u0642\u0627\u062f\u06cc\u0631 \u0646\u0627\u062f\u0631\u0633\u062a  \u0641\u0642\u0637 \u0645\u0642\u0627\u062f\u06cc\u0631 \u0631\u0627 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%D8%A8%D8%B1%D8%AE%DB%8C_%D9%88_%D9%87%D8%B1\"><\/span>\n<p>  \u0628\u0631\u062e\u06cc \u0648 \u0647\u0631<br \/>\n<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0622\u0646\u0647\u0627 \u0645\u0648\u0627\u0631\u062f \u0633\u0631\u06af\u0631\u0645 \u06a9\u0646\u0646\u062f\u0647 \u0627\u06cc \u0647\u0633\u062a\u0646\u062f \u06a9\u0647 \u067e\u0633 \u0627\u0632 \u06cc\u0627\u062f\u06af\u06cc\u0631\u06cc \u062f\u0631 \u0645\u0648\u0631\u062f \u0634\u0645\u0627 \u0645\u0648\u0627\u0631\u062f \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0631\u0627 \u062f\u0631 \u0647\u0645\u0647 \u062c\u0627 \u067e\u06cc\u062f\u0627 \u062e\u0648\u0627\u0647\u06cc\u062f \u06a9\u0631\u062f!<\/p>\n<p>\u0645\u0639\u0645\u0648\u0644\u0627\u064b \u0645\u0648\u0631\u062f \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0628\u0647 \u0635\u0648\u0631\u062a \u0632\u06cc\u0631 \u0627\u0633\u062a: <code>filter(\/* for something *\/).length \/* (not) equal to something *\/<\/code> \u06cc\u0627 <code>Boolean(find(\/* something (not) equal *\/))<\/code> . <\/p>\n<p>\u0628\u0631\u0627\u06cc \u0647\u0631 \u0639\u0646\u0635\u0631 \u062f\u0631 \u0622\u0631\u0627\u06cc\u0647\u060c <code>some<\/code> \u0627\u06af\u0631 \u062d\u062f\u0627\u0642\u0644 \u06cc\u06a9\u06cc \u0627\u0632 \u06af\u0632\u0627\u0631\u0647 \u0639\u0628\u0648\u0631 \u06a9\u0646\u062f true \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f\u060c <code>every<\/code> \u0627\u06af\u0631 \u0647\u0645\u0647 \u0627\u0632 \u0622\u0646 \u0639\u0628\u0648\u0631 \u06a9\u0646\u0646\u062f<\/p>\n<div class=\"highlight js-code-highlight\">\n<pre class=\"highlight javascript\"><code><span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">some<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">===<\/span> <span class=\"mi\">0<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ true<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">every<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">===<\/span> <span class=\"mi\">0<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ false<\/span>\n<\/code><\/pre>\n<div class=\"highlight__panel js-actions-panel\">\n<div class=\"highlight__panel-action js-fullscreen-code-action\">\n    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-on\"><title>\u0648\u0627\u0631\u062f \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M16 3h6v6h-2V5h-4V3zM2 3h6v2H4v4H2V3zm18 16v-4h2v6h-6v-2h4zM4 19h4v2H2v-6h2v4z\"\/>\n<\/svg><\/p>\n<p>    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-off\"><title>\u0627\u0632 \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u062e\u0627\u0631\u062c \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M18 7h4v2h-6V3h2v4zM8 9H2V7h4V3h2v6zm10 8v4h-2v-6h6v2h-4zM8 15v6H6v-4H2v-2h6z\"\/>\n<\/svg><\/p>\n<\/div>\n<\/div>\n<\/div>\n<p>\u06cc\u06a9 \u0686\u06cc\u0632 \u062c\u0627\u0644\u0628 \u0627\u06cc\u0646 \u0627\u0633\u062a \u06a9\u0647 \u0647\u0631 \u062f\u0648 \u0632\u0648\u062f\u062a\u0631 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0646\u062f\u060c <code>some<\/code> \u062f\u0631 \u0627\u0648\u0644 <code>truthy<\/code> \u0627\u0631\u0632\u0634 \u0628\u0627\u0632\u06af\u0634\u062a\u06cc \u0648 <code>every<\/code> \u062f\u0631 \u0627\u0648\u0644 <code>falsy<\/code> \u0645\u0642\u062f\u0627\u0631 \u0628\u0627\u0632\u06af\u0634\u062a\u06cc <\/p>\n<p>\u0647\u0646\u06af\u0627\u0645\u06cc \u06a9\u0647 \u062a\u0646\u0647\u0627 \u0686\u06cc\u0632\u06cc \u06a9\u0647 \u0646\u06cc\u0627\u0632 \u062f\u0627\u0631\u06cc\u062f \u06cc\u06a9 \u0628\u0648\u0644\u06cc \u0627\u0632 \u0627\u06af\u0631 \u0686\u06cc\u0632\u06cc \u0648\u062c\u0648\u062f \u062f\u0627\u0631\u062f \u06cc\u0627 \u0646\u0647 \u0627\u0633\u062a\u060c \u0627\u0632 \u0647\u0631 \u06a9\u062f\u0627\u0645 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f <code>some<\/code> \u06cc\u0627 <code>every<\/code>.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%D9%BE%DB%8C%D8%AF%D8%A7_%DA%A9%D8%B1%D8%AF%D9%86_%D9%88_%D9%BE%DB%8C%D8%AF%D8%A7_%DA%A9%D8%B1%D8%AF%D9%86_%D8%A7%DB%8C%D9%86%D8%AF%DA%A9%D8%B3\"><\/span>\n<p>  \u067e\u06cc\u062f\u0627 \u06a9\u0631\u062f\u0646 \u0648 \u067e\u06cc\u062f\u0627 \u06a9\u0631\u062f\u0646 \u0627\u06cc\u0646\u062f\u06a9\u0633<br \/>\n<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><code>find<\/code>  \u0627\u0648\u0644\u06cc\u0646 \u0639\u0646\u0635\u0631\u06cc \u0631\u0627 \u06a9\u0647 \u0627\u0632 \u06af\u0632\u0627\u0631\u0647 \u06cc\u0627 \u0639\u0628\u0648\u0631 \u0645\u06cc \u06a9\u0646\u062f \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f <code>undefined<\/code> \u062f\u0631 \u063a\u06cc\u0631 \u0627\u06cc\u0646 \u0635\u0648\u0631\u062a\u060c <code>findIndex<\/code> \u0627\u06cc\u0646\u062f\u06a9\u0633 \u0639\u0646\u0635\u0631 \u06cc\u0627 \u0631\u0627 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f <code>-1<\/code> \u062f\u0631 \u063a\u06cc\u0631 \u0627\u06cc\u0646 \u0635\u0648\u0631\u062a.<\/p>\n<p>\u0647\u0631 \u062f\u0648 \u0627\u0632 \u0641\u0647\u0631\u0633\u062a \u0634\u0631\u0648\u0639 \u0628\u0647 \u062c\u0633\u062a\u062c\u0648 \u0645\u06cc \u06a9\u0646\u0646\u062f <code>0<\/code>\u060c \u0627\u0645\u0627 \u0627\u06af\u0631 \u0622\u062e\u0631\u06cc\u0646 \u0645\u0648\u0631\u062f \u0631\u0627 \u0645\u06cc \u062e\u0648\u0627\u0647\u06cc\u062f\u060c \u0627\u0632 \u062a\u063a\u06cc\u06cc\u0631\u0627\u062a &#8220;\u0622\u062e\u0631\u06cc\u0646&#8221; \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f.<\/p>\n<div class=\"highlight js-code-highlight\">\n<pre class=\"highlight javascript\"><code><span class=\"c1\">\/\/ returns the element:<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">find<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">!==<\/span> <span class=\"mi\">0<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ 1<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">findLast<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">!==<\/span> <span class=\"mi\">0<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ 3<\/span>\n\n<span class=\"c1\">\/\/ return the index:<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">findIndex<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">!==<\/span> <span class=\"mi\">0<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ 0<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">findLastIndex<\/span><span class=\"p\">(<\/span><span class=\"nx\">element<\/span> <span class=\"o\">=&gt;<\/span> <span class=\"nx\">element<\/span> <span class=\"o\">%<\/span> <span class=\"mi\">2<\/span> <span class=\"o\">!==<\/span> <span class=\"mi\">0<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ 2<\/span>\n<\/code><\/pre>\n<div class=\"highlight__panel js-actions-panel\">\n<div class=\"highlight__panel-action js-fullscreen-code-action\">\n    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-on\"><title>\u0648\u0627\u0631\u062f \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M16 3h6v6h-2V5h-4V3zM2 3h6v2H4v4H2V3zm18 16v-4h2v6h-6v-2h4zM4 19h4v2H2v-6h2v4z\"\/>\n<\/svg><\/p>\n<p>    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-off\"><title>\u0627\u0632 \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u062e\u0627\u0631\u062c \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M18 7h4v2h-6V3h2v4zM8 9H2V7h4V3h2v6zm10 8v4h-2v-6h6v2h-4zM8 15v6H6v-4H2v-2h6z\"\/>\n<\/svg><\/p>\n<\/div>\n<\/div>\n<\/div>\n<h2><span class=\"ez-toc-section\" id=\"%D8%B4%D8%A7%D9%85%D9%84_%D9%85%DB%8C_%D8%B4%D9%88%D8%AF\"><\/span>\n<p>  \u0634\u0627\u0645\u0644 \u0645\u06cc \u0634\u0648\u062f<br \/>\n<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u06af\u0627\u0647\u06cc \u0627\u0648\u0642\u0627\u062a \u0634\u0645\u0627 \u0641\u0642\u0637 \u0645\u06cc \u062e\u0648\u0627\u0647\u06cc\u062f \u0628\u0631\u0631\u0633\u06cc \u06a9\u0646\u06cc\u062f \u06a9\u0647 \u0622\u06cc\u0627 \u0645\u0642\u062f\u0627\u0631\u06cc \u062f\u0631 \u06cc\u06a9 \u0622\u0631\u0627\u06cc\u0647 \u0648\u062c\u0648\u062f \u062f\u0627\u0631\u062f \u06cc\u0627 \u062e\u06cc\u0631\u060c \u0627\u06cc\u0646 \u06a9\u0627\u0631 \u0628\u0631\u0627\u0628\u0631\u06cc \u0639\u0645\u06cc\u0642 \u0631\u0627 \u0628\u0631\u0631\u0633\u06cc \u0645\u06cc \u06a9\u0646\u062f.<\/p>\n<div class=\"highlight js-code-highlight\">\n<pre class=\"highlight javascript\"><code><span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">includes<\/span><span class=\"p\">(<\/span><span class=\"mi\">1<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ true<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">].<\/span><span class=\"nx\">includes<\/span><span class=\"p\">(<\/span><span class=\"dl\">'<\/span><span class=\"s1\">1<\/span><span class=\"dl\">'<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ false<\/span>\n<\/code><\/pre>\n<div class=\"highlight__panel js-actions-panel\">\n<div class=\"highlight__panel-action js-fullscreen-code-action\">\n    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-on\"><title>\u0648\u0627\u0631\u062f \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M16 3h6v6h-2V5h-4V3zM2 3h6v2H4v4H2V3zm18 16v-4h2v6h-6v-2h4zM4 19h4v2H2v-6h2v4z\"\/>\n<\/svg><\/p>\n<p>    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-off\"><title>\u0627\u0632 \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u062e\u0627\u0631\u062c \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M18 7h4v2h-6V3h2v4zM8 9H2V7h4V3h2v6zm10 8v4h-2v-6h6v2h-4zM8 15v6H6v-4H2v-2h6z\"\/>\n<\/svg><\/p>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0628\u0647 \u0627\u062d\u062a\u0645\u0627\u0644 \u0632\u06cc\u0627\u062f\u060c \u0645\u0627 \u0645\u06cc \u062a\u0648\u0627\u0646\u06cc\u0645 \u062f\u0631 \u0627\u06cc\u0646\u062c\u0627 \u0648\u0627\u0631\u062f \u06a9\u0646\u06cc\u0645 <code>indexOf<\/code> \u0648 <code>lastIndexOf<\/code> \u0647\u0631 \u062f\u0648 \u06cc\u06a9 \u0645\u0642\u062f\u0627\u0631 \u0631\u0627 \u0628\u0631\u0631\u0633\u06cc \u0645\u06cc \u06a9\u0646\u0646\u062f\u060c \u0627\u0645\u0627 \u0634\u0627\u062e\u0635 \u06cc\u0627 \u0631\u0627 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f <code>-1<\/code> \u062f\u0631 \u063a\u06cc\u0631 \u0627\u06cc\u0646 \u0635\u0648\u0631\u062a.<\/p>\n<div class=\"highlight js-code-highlight\">\n<pre class=\"highlight javascript\"><code><span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">0<\/span><span class=\"p\">,<\/span> <span class=\"mi\">1<\/span><span class=\"p\">].<\/span><span class=\"nx\">indexOf<\/span><span class=\"p\">(<\/span><span class=\"mi\">1<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ 0<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">0<\/span><span class=\"p\">,<\/span> <span class=\"mi\">1<\/span><span class=\"p\">].<\/span><span class=\"nx\">indexOf<\/span><span class=\"p\">(<\/span><span class=\"dl\">'<\/span><span class=\"s1\">1<\/span><span class=\"dl\">'<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ -1<\/span>\n\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">0<\/span><span class=\"p\">,<\/span> <span class=\"mi\">1<\/span><span class=\"p\">].<\/span><span class=\"nx\">lastIndexOf<\/span><span class=\"p\">(<\/span><span class=\"mi\">1<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ 2<\/span>\n<span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">0<\/span><span class=\"p\">,<\/span> <span class=\"mi\">1<\/span><span class=\"p\">].<\/span><span class=\"nx\">lastIndexOf<\/span><span class=\"p\">(<\/span><span class=\"dl\">'<\/span><span class=\"s1\">1<\/span><span class=\"dl\">'<\/span><span class=\"p\">);<\/span> <span class=\"c1\">\/\/ -1<\/span>\n<\/code><\/pre>\n<div class=\"highlight__panel js-actions-panel\">\n<div class=\"highlight__panel-action js-fullscreen-code-action\">\n    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-on\"><title>\u0648\u0627\u0631\u062f \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M16 3h6v6h-2V5h-4V3zM2 3h6v2H4v4H2V3zm18 16v-4h2v6h-6v-2h4zM4 19h4v2H2v-6h2v4z\"\/>\n<\/svg><\/p>\n<p>    <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" class=\"highlight-action crayons-icon highlight-action--fullscreen-off\"><title>\u0627\u0632 \u062d\u0627\u0644\u062a \u062a\u0645\u0627\u0645 \u0635\u0641\u062d\u0647 \u062e\u0627\u0631\u062c \u0634\u0648\u06cc\u062f<\/title>\n    <path d=\"M18 7h4v2h-6V3h2v4zM8 9H2V7h4V3h2v6zm10 8v4h-2v-6h6v2h-4zM8 15v6H6v-4H2v-2h6z\"\/>\n<\/svg><\/p>\n<\/div>\n<\/div>\n<\/div>\n<p>\u0645\u0648\u0631\u062f \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0628\u0631\u0627\u06cc <code>includes<\/code> \u062f\u0631 \u0627\u06cc\u0646 \u0645\u06cc\u0627\u0646 \u0645\u0639\u0645\u0648\u0644\u0627\u064b \u062f\u0631 \u062d\u0627\u0644 \u062c\u0633\u062a\u062c\u0648\u06cc \u0622\u0631\u0627\u06cc\u0647 \u0627\u06cc \u0627\u0632 \u0645\u0642\u0627\u062f\u06cc\u0631 \u0627\u0648\u0644\u06cc\u0647 (\u0631\u0634\u062a\u0647\u060c \u0639\u062f\u062f\u060c \u0646\u0645\u0627\u062f\u0647\u0627&#8230;) \u0627\u0633\u062a. <code>some<\/code> \u0648 <code>every<\/code> \u0628\u0631\u0627\u06cc \u0686\u06cc\u0632\u0647\u0627\u06cc \u067e\u06cc\u0686\u06cc\u062f\u0647 \u062a\u0631 \u0627\u0632 \u0627\u06cc\u0646\u06a9\u0647 \u0645\u0642\u062f\u0627\u0631 \u0648\u062c\u0648\u062f \u062f\u0627\u0631\u062f \u06cc\u0627 \u0646\u0647 \u06cc\u0627 \u0628\u0631\u0627\u06cc \u0627\u0634\u06cc\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0645\u06cc \u0634\u0648\u062f.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%D8%A2%D8%AE%D8%B1%DB%8C%D9%86_%D8%A7%D8%B8%D9%87%D8%A7%D8%B1%D8%A7%D8%AA\"><\/span>\n<p>  \u0622\u062e\u0631\u06cc\u0646 \u0627\u0638\u0647\u0627\u0631\u0627\u062a<br \/>\n<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0627\u0633\u0646\u0627\u062f MDN \u0628\u0647 \u0647\u0645\u0627\u0646 \u0627\u0646\u062f\u0627\u0632\u0647 \u06a9\u0647 \u0645\u06cc \u0622\u06cc\u0646\u062f \u062e\u0648\u0628 \u0647\u0633\u062a\u0646\u062f.  \u0645\u0645\u06a9\u0646 \u0627\u0633\u062a \u0646\u062f\u0627\u0646\u06cc\u062f \u06a9\u0647 \u0647\u0645\u0647 \u0622\u0646\u0647\u0627 \u0648\u062c\u0648\u062f \u062f\u0627\u0631\u0646\u062f\u060c \u0627\u0645\u0627 \u0632\u0645\u0627\u0646\u06cc \u06a9\u0647 \u0645\u062a\u0648\u062c\u0647 \u0634\u0648\u06cc\u062f \u0622\u0646\u0647\u0627 \u06a9\u0627\u0645\u0644\u0627\u064b \u0633\u0627\u062f\u0647 \u0647\u0633\u062a\u0646\u062f. <\/p>\n<p>\u0633\u067e\u0633\u060c \u0645\u0645\u06a9\u0646 \u0627\u0633\u062a \u0628\u0631\u062e\u06cc \u0627\u0632 \u0627\u0641\u0631\u0627\u062f \u0628\u062f\u0627\u0646\u0646\u062f \u06a9\u0647 \u0631\u0648\u0634 \u0647\u0627 \u0648\u062c\u0648\u062f \u062f\u0627\u0631\u062f\u060c \u0627\u0645\u0627 \u0646\u062d\u0648\u0647 \u0628\u0647 \u06a9\u0627\u0631\u06af\u06cc\u0631\u06cc \u0622\u0646\u0647\u0627 \u0631\u0627 \u0646\u062f\u0627\u0646\u0646\u062f.  \u0628\u0646\u0627\u0628\u0631\u0627\u06cc\u0646\u060c \u0627\u06af\u0631 \u0645\u06cc \u062e\u0648\u0627\u0647\u06cc\u062f\u060c \u0646\u0645\u0648\u0646\u0647 \u0647\u0627\u06cc\u06cc \u0631\u0627 \u0628\u0641\u0631\u0633\u062a\u06cc\u062f \u06a9\u0647 \u0646\u0645\u06cc \u062f\u0627\u0646\u06cc\u062f \u0686\u06af\u0648\u0646\u0647 \u0631\u0648\u0634 \u0647\u0627 \u0631\u0627 \u0627\u0639\u0645\u0627\u0644 \u06a9\u0646\u06cc\u062f \u0648 \u0645\u0646 \u0645\u06cc \u062a\u0648\u0627\u0646\u0645 \u06af\u0632\u06cc\u0646\u0647 \u0647\u0627 \u0631\u0627 \u0627\u0635\u0644\u0627\u062d \u06a9\u0646\u0645.<\/p>\n<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u0628\u0647 \u0646\u0648\u0639\u06cc\u060c \u0628\u0647 \u0646\u0648\u0639\u06cc\u060c \u0645\u0631\u062f\u0645 \u0641\u06a9\u0631 \u0645\u06cc \u06a9\u0646\u0646\u062f for \u062f\u0631\u06a9 \u0648 \u062f\u0631\u06a9 \u062d\u0644\u0642\u0647 \u0647\u0627 \u0622\u0633\u0627\u0646 \u062a\u0631 \u0627\u0633\u062a&#8230; \u0645\u0646 \u0627\u06cc\u0646\u062c\u0627 \u0647\u0633\u062a\u0645 \u062a\u0627 \u0622\u0646 \u0631\u0627 \u062a\u063a\u06cc\u06cc\u0631 \u062f\u0647\u0645. \u0645\u0646 \u0627\u0632 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u062e\u0648\u0627\u0647\u0645 \u06a9\u0631\u062f\u060c \u0627\u0645\u0627 \u0628\u06cc\u0634\u062a\u0631 \u0632\u0628\u0627\u0646\u200c\u0647\u0627 \u0631\u0648\u0634\u200c\u0647\u0627 \u0631\u0627 \u0628\u0647 \u0631\u0648\u0634\u06cc \u062f\u06cc\u06af\u0631 \u067e\u06cc\u0627\u062f\u0647\u200c\u0633\u0627\u0632\u06cc \u0645\u06cc\u200c\u06a9\u0646\u0646\u062f\u060c \u06af\u0627\u0647\u06cc \u0627\u0648\u0642\u0627\u062a \u0628\u0627 \u06a9\u0645\u06cc \u062a\u0641\u0627\u0648\u062a \u062f\u0631 \u0646\u0627\u0645\u200c\u06af\u0630\u0627\u0631\u06cc. \u0645\u0628\u0627\u0646\u06cc \u0627\u06a9\u062b\u0631 \u0631\u0648\u0634 \u0647\u0627\u060c \u0628\u0647 \u0627\u0633\u062a\u062b\u0646\u0627\u06cc &hellip;<\/p>\n","protected":false},"author":2,"featured_media":30688,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"","fifu_image_alt":"","footnotes":""},"categories":[339],"tags":[],"class_list":["post-30687","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-dev"],"_links":{"self":[{"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/posts\/30687","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/comments?post=30687"}],"version-history":[{"count":0,"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/posts\/30687\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/media\/30688"}],"wp:attachment":[{"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/media?parent=30687"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/categories?post=30687"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nabfollower.com\/blog\/wp-json\/wp\/v2\/tags?post=30687"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}