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30-seconds-of-code/snippets/call.md
Angelos Chalaris 8a6b73bd0c Update covers
2023-02-16 22:24:28 +02:00

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---
title: Call functions with context
tags: function
cover: rabbit-call
firstSeen: 2017-12-22T21:54:30+02:00
lastUpdated: 2021-06-13T13:50:25+03:00
---
Given a key and a set of arguments, call them when given a context.
- Use a closure to call `key` with `args` for the given `context`.
```js
const call = (key, ...args) => context => context[key](...args);
```
```js
Promise.resolve([1, 2, 3])
.then(call('map', x => 2 * x))
.then(console.log); // [ 2, 4, 6 ]
const map = call.bind(null, 'map');
Promise.resolve([1, 2, 3])
.then(map(x => 2 * x))
.then(console.log); // [ 2, 4, 6 ]
```