await-reduce/README.md

Resolve and reduce an array of promises

# await-reduce [![](https://img.shields.io/npm/v/await-reduce.svg)](https://www.npmjs.com/package/await-reduce) [![](https://img.shields.io/badge/source--000000.svg?logo=github&style=social)](https://github.com/omrilotan/mono/tree/master/packages/await-reduce)

Resolve and reduce an array of promises

```js
const reduce = require('await-reduce');
```

The behaviour matches Array.prototype.reduce.

```js
const results = await reduce(
	[
		fetch('one').then(res => res.json()),
		fetch('two').then(res => res.json()),
		fetch('ten').then(res => res.json()),
	],
	(accumulator, item) => [...accumulator, item],
	[]
)
```

The callback matches Array.prototype.reduce's 4 argument signature, except the 4th argument (`array`) are the results of the Promises, and the callback itself can be asynchronous as well.
```js
const results = await reduce(
	[
		fetch('one'),
		fetch('two'),
		fetch('ten'),
	],
	async (accumulator, response, index, array) => {
		if (!response.ok) {
			return accumulator
		}
		const data = await response.json()
		return Object.assign(accumulator, data)
	},
	{}
)
```

## Transpiled version
Environments which exclude node_modules from the transpiling pipeline should include the "browser" entry instead of "main". This exposes an ES5 commonjs module.

Also available for explicit import:
```js
const reduce = require('await-reduce/dist');
```