23 lines
602 B
Markdown
23 lines
602 B
Markdown
---
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title: Run promises in series
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type: snippet
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tags: [function,promise]
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cover: sail-away
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dateModified: 2020-10-22T20:24:30+03:00
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---
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Runs an array of promises in series.
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- Use `Array.prototype.reduce()` to create a promise chain, where each promise returns the next promise when resolved.
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```js
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const runPromisesInSeries = ps =>
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ps.reduce((p, next) => p.then(next), Promise.resolve());
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```
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```js
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const delay = d => new Promise(r => setTimeout(r, d));
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runPromisesInSeries([() => delay(1000), () => delay(2000)]);
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// Executes each promise sequentially, taking a total of 3 seconds to complete
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```
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