24 lines
662 B
Markdown
24 lines
662 B
Markdown
---
|
|
title: Run promises in series
|
|
tags: function,promise
|
|
expertise: intermediate
|
|
cover: blog_images/sail-away.jpg
|
|
firstSeen: 2017-12-17T17:55:51+02:00
|
|
lastUpdated: 2020-10-22T20:24:30+03:00
|
|
---
|
|
|
|
Runs an array of promises in series.
|
|
|
|
- Use `Array.prototype.reduce()` to create a promise chain, where each promise returns the next promise when resolved.
|
|
|
|
```js
|
|
const runPromisesInSeries = ps =>
|
|
ps.reduce((p, next) => p.then(next), Promise.resolve());
|
|
```
|
|
|
|
```js
|
|
const delay = d => new Promise(r => setTimeout(r, d));
|
|
runPromisesInSeries([() => delay(1000), () => delay(2000)]);
|
|
// Executes each promise sequentially, taking a total of 3 seconds to complete
|
|
```
|