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https://github.com/huruji/p-first
make your Promise support getting first fulfilled Promise
https://github.com/huruji/p-first
Last synced: 3 months ago
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make your Promise support getting first fulfilled Promise
- Host: GitHub
- URL: https://github.com/huruji/p-first
- Owner: huruji
- Created: 2019-04-30T04:05:19.000Z (about 5 years ago)
- Default Branch: master
- Last Pushed: 2019-04-30T07:32:52.000Z (about 5 years ago)
- Last Synced: 2024-03-17T15:21:05.912Z (3 months ago)
- Language: TypeScript
- Size: 5.86 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
Lists
- awesome-github-star - p-first
README
中文 | [English](./README_EN.md)
# p-first
让你的 Promise 支持获取第一个变为 fulfilled 状态的函数
> 不同于 `Promise.race` 不管是 fulfilled 或者是 rejected 状态都会返回
## How to use
```bash
npm i p-first -S
```
```js
import first from 'p-first'
first(yourPromises)
```
或者你可以拓展你的 `Promise` 构造函数
```js
Promise.first = first
```
## real world use
你有两个 Ajax api 获取相同的数据，但是你不知道哪个 Ajax api 会先返回，也无法预测哪个 Ajax api 会出问题, 你可以使用 `p-first` 来获取**第一个成功返回**的数据
```js
const p1 = new Promise(resolve => {
setTimeout(() => {
resolve (12)
}, 5000)
})
const p2 = new Promise(resolve => {
setTimeout (() => {
resolve ('huruji')
}, 1000)
})
const p3 = new Promise((resolve, reject) => {
reject(404)
})
Promise.first([p1, p3, p2]).then(data => {
console.log(data)
})
// output: huruji
```
## catch error
当没有一个 Promise 变为了 fulfilled 状态，你可以在 `.catch` 中捕获 error
```js
const p1 = new Promise((resolve, reject) => {
setTimeout(() => {
reject (12)
}, 5000)
})
const p2 = new Promise((resolve, reject) => {
setTimeout (() => {
reject('huruji')
}, 1000)
})
const p3 = new Promise((resolve, reject) => {
reject(404)
})
Promise.first([p1, p3, p2]).then(data => {
console.log(data)
}).catch((errs) => {
console.log('have errors')
console.log(errs)
})
// have errors
// [12, 404, 'huruji']
```