84 lines
2.0 KiB
Plaintext
84 lines
2.0 KiB
Plaintext
# p-filter [](https://travis-ci.org/sindresorhus/p-filter)
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> Filter promises concurrently
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Useful when you need to run promise-returning & async functions multiple times with different inputs concurrently and get a filtered down result.
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## Install
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```
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$ npm install p-filter
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```
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## Usage
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```js
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const pFilter = require('p-filter');
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const getWeather = require('get-weather'); // not a real module
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const places = [
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getCapital('Norway').then(info => info.name),
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'Bangkok, Thailand',
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'Berlin, Germany',
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'Tokyo, Japan'
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];
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const filterer = async place => {
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const weather = await getWeather(place);
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return weather.temperature > 30;
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};
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(async () => {
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const result = await pFilter(places, filterer);
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console.log(result);
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//=> ['Bangkok, Thailand']
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})();
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```
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## API
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### pFilter(input, filterer, [options])
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Returns a `Promise` that is fulfilled when all promises in `input` and ones returned from `filterer` are fulfilled, or rejects if any of the promises reject. The fulfilled value is an `Array` of the fulfilled values returned from `filterer` in `input` order.
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#### input
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Type: `Iterable<Promise|any>`
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Iterated over concurrently in the `filterer` function.
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#### filterer(element, index)
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Type: `Function`
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The filterer function that decides whether an element should be included into result. Expected to return `boolean | Promise<boolean>`.
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#### options
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Type: `Object`
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##### concurrency
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Type: `number`<br>
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Default: `Infinity`<br>
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Minimum: `1`
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Number of concurrently pending promises returned by `filterer`.
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## Related
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- [p-locate](https://github.com/sindresorhus/p-locate) - Get the first fulfilled promise that satisfies the provided testing function
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- [p-map](https://github.com/sindresorhus/p-map) - Map over promises concurrently
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- [p-times](https://github.com/sindresorhus/p-times) - Run promise-returning & async functions a specific number of times concurrently
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- [More…](https://github.com/sindresorhus/promise-fun)
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## License
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MIT © [Sindre Sorhus](https://sindresorhus.com)
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