it-pipe
Version:
Utility to "pipe" async iterables together
91 lines (63 loc) • 3.11 kB
Markdown
# it-pipe <!-- omit in toc -->
[](https://codecov.io/gh/alanshaw/it-pipe)
[](https://github.com/alanshaw/it-pipe/actions/workflows/js-test-and-release.yml?query=branch%3Amaster)
> Utility to "pipe" async iterables together
## Table of contents <!-- omit in toc -->
- [Install](#install)
- [Browser `<script>` tag](#browser-script-tag)
- [Usage](#usage)
- [API](#api)
- [`pipe(firstFn, ...fns)`](#pipefirstfn-fns)
- [API Docs](#api-docs)
- [License](#license)
- [Contribution](#contribution)
## Install
```console
$ npm i it-pipe
```
### Browser `<script>` tag
Loading this module through a script tag will make it's exports available as `ItPipe` in the global namespace.
```html
<script src="https://unpkg.com/it-pipe/dist/index.min.js"></script>
```
Based on this definition of streaming iterables <https://gist.github.com/alanshaw/591dc7dd54e4f99338a347ef568d6ee9>.
Almost identical to the [`pipeline`](https://github.com/bustle/streaming-iterables#pipeline) function from the [`streaming-iterables`](https://www.npmjs.com/package/streaming-iterables) module except that it supports duplex streams *and* will automatically wrap a "source" as the first param in a function.
## Usage
```js
import { pipe } from 'it-pipe'
const result = await pipe(
// A source is just an iterable, this is shorthand for () => [1, 2, 3]
[1, 2, 3],
// A transform takes a source, and returns a source.
// This transform doubles each value asynchronously.
function transform (source) {
return (async function * () { // A generator is async iterable
for await (const val of source) yield val * 2
})()
},
// A sink, it takes a source and consumes it, optionally returning a value.
// This sink buffers up all the values from the source and returns them.
async function collect (source) {
const vals = []
for await (const val of source) {
vals.push(val)
}
return vals
}
)
console.log(result) // 2,4,6
```
## API
### `pipe(firstFn, ...fns)`
Calls `firstFn` and then every function in `fns` with the result of the previous function. The final return is the result of the last function in `fns`.
Note:
- `firstFn` may be a `Function` or an `Iterable`
- `firstFn` or any of `fns` may be a [duplex object](https://gist.github.com/alanshaw/591dc7dd54e4f99338a347ef568d6ee9#duplex-it) (an object with a `sink` and `source`).
## API Docs
- <https://alanshaw.github.io/it-pipe>
## License
Licensed under either of
- Apache 2.0, ([LICENSE-APACHE](LICENSE-APACHE) / <http://www.apache.org/licenses/LICENSE-2.0>)
- MIT ([LICENSE-MIT](LICENSE-MIT) / <http://opensource.org/licenses/MIT>)
## Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.