هنوز با وعده های جاوا اسکریپت مبارزه می کنید؟

const myPromise = new Promise((resolve, reject) => {
  // Asynchronous task:
  setTimeout(() => {
    resolve("Promise resolved after 1 second");
  }, 1000);
});

// using .then(), .catch(), and .finally()
myPromise
  .then((successValue) => console.log(successValue)) // .then to handle success
  .catch((error) => console.error(error)); // .catch to handle error
  .finally(() => console.log('Process completed')); // Handle both success and error cases

// using try/catch and async/await
try {
  const successValue = await myPromise; // your code will be here until the process ends
  console.log(successValue);
} catch (error) {
  console.error(error);
} finally {
  console.log('Process completed.'); // This will run regardless of success or error
}

function fetchUser(userId) {} // it returns a promise
function fetchPosts(userId) {} // it returns a promise
function fetchComments(postId) {} // it returns a promise

// Start the promise chain
fetchUser(1)
  .then((user) => {
    console.log("User:", user);
    return fetchPosts(user.id); // Return the next promise
  })
  .then((posts) => {
    console.log("Posts:", posts);
    return fetchComments(posts[0].id); // Return the next promise
  })
  .then((comments) => {
    console.log("Comments:", comments);
  })
  .catch((error) => {
    console.error("Error:", error);
  });

function fetchUser(userId) {} // it returns a promise
function fetchPosts(userId) {} // it returns a promise
function fetchComments(postId) {} // it returns a promise

// Start the promise nesting
fetchUser(1)
  .then((user) => {
    console.log("User:", user);
    return fetchPosts(user.id).then((posts) => {
      console.log("Posts:", posts);
      return fetchComments(posts[0].id).then((comments) => {
        console.log("Comments:", comments);
      });
    });
  })
  .catch((error) => {
    console.error("Error:", error);
  });

  const promise1 = Promise.resolve(3);
  const promise2 = 42;
  const promise3 = new Promise((resolve, reject) => {
    setTimeout(resolve, 100, "foo");
  });

  Promise.all([promise1, promise2, promise3]).then((values) => {
    console.log(values);
  });
  // Expected output: Array [3, 42, "foo"]

  const promise1 = Promise.resolve(3);
  const promise2 = new Promise((resolve, reject) =>
    setTimeout(reject, 100, "foo")
  );
  const promises = [promise1, promise2];

  Promise.allSettled(promises).then((results) =>
    results.forEach((result) => console.log(result.status))
  );

  // Expected output:
  // "fulfilled"
  // "rejected"

  const promise1 = new Promise((resolve, reject) => {
    setTimeout(resolve, 500, "one");
  });
  const promise2 = new Promise((resolve, reject) => {
    setTimeout(resolve, 100, "two");
  });

  Promise.race([promise1, promise2]).then((value) => {
    console.log(value);
    // Both resolve, but promise2 is faster
  });
  // Expected output: "two"

  const fetchFromAPI1 = fetch("https://api.example.com/endpoint1");
  const fetchFromAPI2 = fetch("https://api.example.com/endpoint2");
  const fetchFromAPI3 = fetch("https://api.example.com/endpoint3");

  Promise.any([fetchFromAPI1, fetchFromAPI2, fetchFromAPI3])
    .then((response) => response.json())
    .then((data) => {
      console.log("Received data from the first successful API call:", data);
    })
    .catch((error) => {
      console.error("All API calls failed:", error);
    });