87 lines
2.0 KiB
Markdown
87 lines
2.0 KiB
Markdown
# p-locate [](https://travis-ci.org/sindresorhus/p-locate)
|
|
|
|
> Get the first fulfilled promise that satisfies the provided testing function
|
|
|
|
Think of it like an async version of [`Array#find`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/find).
|
|
|
|
|
|
## Install
|
|
|
|
```
|
|
$ npm install --save p-locate
|
|
```
|
|
|
|
|
|
## Usage
|
|
|
|
Here we find the first file that exists on disk, in array order.
|
|
|
|
```js
|
|
const pathExists = require('path-exists');
|
|
const pLocate = require('p-locate');
|
|
|
|
const files = [
|
|
'unicorn.png',
|
|
'rainbow.png', // only this one actually exists on disk
|
|
'pony.png'
|
|
];
|
|
|
|
pLocate(files, file => pathExists(file)).then(foundPath => {
|
|
console.log(foundPath);
|
|
//=> 'rainbow'
|
|
});
|
|
```
|
|
|
|
*The above is just an example. Use [`locate-path`](https://github.com/sindresorhus/locate-path) if you need this.*
|
|
|
|
|
|
## API
|
|
|
|
### pLocate(input, tester, [options])
|
|
|
|
Returns a `Promise` that is fulfilled when `tester` resolves to `true` or the iterable is done, or rejects if any of the promises reject. The fulfilled value is the current iterable value or `undefined` if `tester` never resolved to `true`.
|
|
|
|
#### input
|
|
|
|
Type: `Iterable<Promise|any>`
|
|
|
|
#### tester(element)
|
|
|
|
Type: `Function`
|
|
|
|
Expected to return a `Promise<boolean>` or boolean.
|
|
|
|
#### options
|
|
|
|
Type: `Object`
|
|
|
|
##### concurrency
|
|
|
|
Type: `number`<br>
|
|
Default: `Infinity`<br>
|
|
Minimum: `1`
|
|
|
|
Number of concurrently pending promises returned by `tester`.
|
|
|
|
##### preserveOrder
|
|
|
|
Type: `boolean`<br>
|
|
Default: `true`
|
|
|
|
Preserve `input` order when searching.
|
|
|
|
Disable this to improve performance if you don't care about the order.
|
|
|
|
|
|
## Related
|
|
|
|
- [p-map](https://github.com/sindresorhus/p-map) - Map over promises concurrently
|
|
- [p-filter](https://github.com/sindresorhus/p-filter) - Filter promises concurrently
|
|
- [p-any](https://github.com/sindresorhus/p-any) - Wait for any promise to be fulfilled
|
|
- [More…](https://github.com/sindresorhus/promise-fun)
|
|
|
|
|
|
## License
|
|
|
|
MIT © [Sindre Sorhus](https://sindresorhus.com)
|