mirror of
https://github.com/alrayyes/wiki.git
synced 2024-11-29 14:36:22 +00:00
38 lines
620 B
Markdown
38 lines
620 B
Markdown
---
|
|
id: 03f42b69-8321-443f-9d1d-fb7814999dd7
|
|
title: JavaScript Async Functions
|
|
---
|
|
|
|
# Introduction
|
|
|
|
Async Functions[^1] is a new feature implemented in
|
|
[ES2017](20201026104538-es2017) to handle
|
|
[promises](20200911154351-promises).
|
|
|
|
# Syntax
|
|
|
|
## Fulfilling a promise
|
|
|
|
``` javascript
|
|
async function asyncFunc() {
|
|
return 123;
|
|
}
|
|
|
|
asyncFunc().then((x) => console.log(x));
|
|
// 123
|
|
```
|
|
|
|
## Rejecting a promise
|
|
|
|
``` javascript
|
|
async function asyncFunc() {
|
|
throw new Error("Problem!");
|
|
}
|
|
|
|
asyncFunc().catch((err) => console.log(err));
|
|
// Error: Problem!
|
|
```
|
|
|
|
# Footnotes
|
|
|
|
[^1]: <https://github.com/tc39/ecmascript-asyncawait>
|