In Vue.js, await and async are used to handle asynchronous requests and events. await can pause the execution of asynchronous functions until the Promise is resolved, making it convenient to write asynchronous code synchronously. async is used to mark a function as asynchronous, causing it to return a Promise that resolves after the function completes execution. When used together, the two can be used to get data from APIs, listen to user input events, and handle animations and transitions. The best time is during operations that require waiting for results, such as getting data from an API; it should not be used during operations that do not require waiting for results, such as performing calculations.
await and async in Vue
In Vue.js, await
and async
is a powerful tool for handling asynchronous requests and events.
await
await
keyword is used to pause the execution of an asynchronous function until its inner Promise is resolved. It allows you to write asynchronous code in a synchronous manner, making the code easier to read and understand.
<code class="javascript">async function fetchData() { const response = await fetch('/api/data'); const data = await response.json(); return data; }</code>
In the above example, await fetch()
will pause the execution of the fetchData
function until the API request completes and returns a Promise. await response.json()
then pauses execution again until the Promise is resolved and a JSON object is returned.
async
async
keyword is used to mark a function as asynchronous. It allows functions to return a Promise that is resolved after the function execution completes.
<code class="javascript">const fetchDataAsync = async () => { const response = await fetch('/api/data'); const data = await response.json(); };</code>
In the above example, the fetchDataAsync
function is marked as asynchronous and it returns a Promise that is resolved after the request is completed.
Usage
await
and async
are often used together to handle asynchronous operations. They can be used in a variety of scenarios, including:
When to use
The best time to use await
and async
is when dealing with operations that require waiting for results. For example, if you are getting data from an API, you can use them to pause execution until the data is available.
When not to use it
Don't Use await
and async in operations that don't require waiting for results
. For example, you should not use them if you are just performing some calculations that do not involve asynchronous operations.
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