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30-seconds-of-code/snippets/chainAsync.md
2018-12-12 15:53:48 -06:00

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### chainAsync
Chains asynchronous functions.
Loop through an array of functions containing asynchronous events, calling `next` when each asynchronous event has completed.
```js
const chainAsync = fns => {
let curr = 0;
const last = fns[fns.length - 1];
const next = () => {
const fn = fns[curr++]
fn === last ? fn() : fn(next);
}
next();
};
```
```js
chainAsync([
next => {
console.log('0 seconds');
setTimeout(next, 1000);
},
next => {
console.log('1 second');
setTimeout(next, 1000);
},
() => {
console.log('2 second');
}
]);
```