Files
30-seconds-of-code/snippets/runPromisesInSeries.md
Isabelle Viktoria Maciohsek 5cb69e3c5c Update snippet descriptions
2020-10-22 20:24:30 +03:00

20 lines
539 B
Markdown

---
title: runPromisesInSeries
tags: function,promise,intermediate
---
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
```