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--- java-script:fetch-using-async-await [2023/08/03 14:15] – odefta
+++ java-script:fetch-using-async-await [2023/08/03 14:27] (current) – odefta
@@ Line 1: / Line 1: @@
 ====== Fetch using async/await ======
-Async/Await is part of the ES2017 specification and provides a more streamlined syntax for dealing with **promises**, leading to cleaner, easier-to-read code. \\
+===== Introduction =====
-The **async** and **await** keywords enable asynchronous, promise-based behavior to be written in a cleaner style, avoiding the need for explicitly chaining promises. These keywords make the asynchronous code look and behave like synchronous code.\\
-However, Async/Await may not be supported in all browsers (although it is supported in most modern browsers), and you may need to use a tool like **[[java-script:babel|Babel]]** to transpile your code for older browser support.
+Async/Await is part of the ES2017 specification and provides a more streamlined syntax for dealing with **promises**, leading to cleaner, easier-to-read code. \\
+Async/Await uses JavaScript fetch API (which returns promises) for making HTTP requests. \\
+ The **async** and **await** keywords enable asynchronous, promise-based behavior to be written in a cleaner style, avoiding the need for explicitly chaining promises. These keywords make the asynchronous code look and behave like synchronous code.
+<note>
+Async/Await may not be supported in all browsers (although it is supported in most modern browsers), and you may need to use a tool like **[[java-script:babel|Babel]]** to transpile your code for older browser support.
+</note>
+===== Advantages over AJAX =====
+Async/Await in JavaScript, which is often used with the Fetch API for making HTTP requests, has several advantages over traditional **[[java-script:ajax-fetch|AJAX]]** techniques:
+  - **Readability**: Async/Await makes asynchronous code look and behave more like synchronous code. This makes the code cleaner and easier to understand.
+  - **Error Handling**: With Async/Await, you can use classic try/catch blocks for error handling, which is more straightforward and intuitive compared to handling errors in callbacks or promise chains.
+  - **Avoiding Callback Hell**: With AJAX and callbacks, code can become nested and complicated very quickly, a situation often referred to as "callback hell". This is avoided with async/await, since each step in an async function appears to be a linear, sequential operation, not a nested one.
+  - **Improved Debugging**: Debugging async/await code is simpler than debugging promises or callbacks. Each async function operates as a smaller self-contained unit which can be stepped through with debugging tools.
+  - **Concurrency Control**: Async/Await makes it easier to control concurrency. For example, with Promise.all() and async/await, you can start several asynchronous tasks all at once and then await them all, which can lead to performance improvements.
+===== Fetch example using async/await (web browser) =====
+We'll use the [[java-script:ajax-fetch|same example]], but with async/await framework instead of ajax:
+<code javascript fetch-async-await.html>
+<!DOCTYPE html>
+<html>
+<body>
+    <div id="data"></div>
+    <script>
+        async function fetchData() {
+            try {
+                const response = await fetch('https://api.github.com/users');
+                const data = await response.json();
+                data.forEach(user => {
+                    const div = document.getElementById('data');
+                    div.innerHTML += `
+                        <img src="${user.avatar_url}" alt="${user.login}'s avatar" width="100"><br>
+                        Login: ${user.login}<br>
+                        ID: ${user.id}<br>
+                        Node ID: ${user.node_id}<br>
+                        Avatar URL: ${user.avatar_url}<br>
+                        Gravatar ID: ${user.gravatar_id}<br>
+                        URL: ${user.url}<br>
+                        HTML URL: ${user.html_url}<br>
+                        Followers URL: ${user.followers_url}<br>
+                        Following URL: ${user.following_url}<br>
+                        Gists URL: ${user.gists_url}<br>
+                        Starred URL: ${user.starred_url}<br>
+                        Subscriptions URL: ${user.subscriptions_url}<br>
+                        Organizations URL: ${user.organizations_url}<br>
+                        Repos URL: ${user.repos_url}<br>
+                        Events URL: ${user.events_url}<br>
+                        Received Events URL: ${user.received_events_url}<br>
+                        Type: ${user.type}<br>
+                        Site Admin: ${user.site_admin}<br>
+                        <hr>
+                    `;
+                });
+            } catch (error) {
+                console.error('Error:', error);
+            }
+        }
+        fetchData();
+    </script>
+</body>
+</html>
+</code>