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https://github.com/stdlib-js/utils-any-by
Test whether at least one element in a collection passes a test implemented by a predicate function.
https://github.com/stdlib-js/utils-any-by
any array-like collection iterate javascript node node-js nodejs predicate stdlib test util utilities utility utils validate
Last synced: 2 days ago
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Test whether at least one element in a collection passes a test implemented by a predicate function.
- Host: GitHub
- URL: https://github.com/stdlib-js/utils-any-by
- Owner: stdlib-js
- License: apache-2.0
- Created: 2021-06-14T13:37:17.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2024-12-01T08:31:35.000Z (about 2 months ago)
- Last Synced: 2025-01-03T12:43:07.490Z (14 days ago)
- Topics: any, array-like, collection, iterate, javascript, node, node-js, nodejs, predicate, stdlib, test, util, utilities, utility, utils, validate
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 905 KB
- Stars: 1
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
Awesome Lists containing this project
README
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# anyBy
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Test whether at least one element in a collection passes a test implemented by a predicate function.
## Installation
```bash
npm install @stdlib/utils-any-by
```
Alternatively,
- To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).
The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
## Usage
```javascript
var anyBy = require( '@stdlib/utils-any-by' );
```
#### anyBy( collection, predicate\[, thisArg ] )
Tests whether at least one element in a `collection` passes a test implemented by a `predicate` function.
```javascript
function isNegative( value ) {
return ( value < 0 );
}
var arr = [ 1, 2, 3, 4, -1 ];
var bool = anyBy( arr, isNegative );
// returns true
```
If a `predicate` function returns a truthy value, the function **immediately** returns `true`.
```javascript
function isPositive( value ) {
if ( value < 0 ) {
throw new Error( 'should never reach this line' );
}
return ( value > 0 );
}
var arr = [ 1, -2, 3, 4 ];
var bool = anyBy( arr, isPositive );
// returns true
```
The invoked `function` is provided three arguments:
- **value**: collection element.
- **index**: collection index.
- **collection**: input collection.
To set the function execution context, provide a `thisArg`.
```javascript
function sum( value ) {
this.sum += value;
this.count += 1;
return ( value < 0 );
}
var arr = [ 1, 2, 3, 4, -5 ];
var context = {
'sum': 0,
'count': 0
};
var bool = anyBy( arr, sum, context );
// returns true
var mean = context.sum / context.count;
// returns 1.0
```
## Notes
- A `collection` may be either an [`Array`][mdn-array], [`Typed Array`][mdn-typed-array], or an array-like [`Object`][mdn-object] (excluding `strings` and `functions`).
- If provided an empty collection, the function returns `false`.
```javascript
function alwaysTrue() {
return true;
}
var bool = anyBy( [], alwaysTrue );
// returns false
```
- The function differs from [`Array.prototype.some`][mdn-array-some] in the following ways:
- The function does **not** skip `undefined` elements.
```javascript
function log( value, index ) {
console.log( '%s: %s', index, value );
return ( value < 0 );
}
var arr = [ 1, , , 4, -1 ];
var bool = anyBy( arr, log );
/* =>
0: 1
1: undefined
2: undefined
3: 4
4: -1
*/
```
- The function provides limited support for dynamic collections (i.e., collections whose `length` changes during execution).
## Examples
```javascript
var randu = require( '@stdlib/random-base-randu' );
var anyBy = require( '@stdlib/utils-any-by' );
function threshold( value ) {
return ( value > 0.95 );
}
var bool;
var arr;
var i;
arr = [];
for ( i = 0; i < 100; i++ ) {
arr.push( randu() );
}
bool = anyBy( arr, threshold );
// returns
```
* * *
## See Also
- [`@stdlib/utils-async/any-by`][@stdlib/utils/async/any-by]: test whether at least one element in a collection passes a test implemented by a predicate function.
- [`@stdlib/utils-any-by-right`][@stdlib/utils/any-by-right]: test whether at least one element in a collection passes a test implemented by a predicate function, iterating from right to left.
- [`@stdlib/utils-every-by`][@stdlib/utils/every-by]: test whether all elements in a collection pass a test implemented by a predicate function.
- [`@stdlib/utils-for-each`][@stdlib/utils/for-each]: invoke a function for each element in a collection.
- [`@stdlib/utils-none-by`][@stdlib/utils/none-by]: test whether all elements in a collection fail a test implemented by a predicate function.
- [`@stdlib/utils-some-by`][@stdlib/utils/some-by]: test whether a collection contains at least `n` elements which pass a test implemented by a predicate function.
* * *
## Notice
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
#### Community
[![Chat][chat-image]][chat-url]
---
## License
See [LICENSE][stdlib-license].
## Copyright
Copyright © 2016-2024. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/utils-any-by.svg
[npm-url]: https://npmjs.org/package/@stdlib/utils-any-by
[test-image]: https://github.com/stdlib-js/utils-any-by/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/utils-any-by/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/utils-any-by/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/utils-any-by?branch=main
[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/utils-any-by/tree/deno
[deno-readme]: https://github.com/stdlib-js/utils-any-by/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/utils-any-by/tree/umd
[umd-readme]: https://github.com/stdlib-js/utils-any-by/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/utils-any-by/tree/esm
[esm-readme]: https://github.com/stdlib-js/utils-any-by/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/utils-any-by/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/utils-any-by/main/LICENSE
[mdn-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array
[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
[mdn-object]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object
[mdn-array-some]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/some
[@stdlib/utils/async/any-by]: https://github.com/stdlib-js/utils-async-any-by
[@stdlib/utils/any-by-right]: https://github.com/stdlib-js/utils-any-by-right
[@stdlib/utils/every-by]: https://github.com/stdlib-js/utils-every-by
[@stdlib/utils/for-each]: https://github.com/stdlib-js/utils-for-each
[@stdlib/utils/none-by]: https://github.com/stdlib-js/utils-none-by
[@stdlib/utils/some-by]: https://github.com/stdlib-js/utils-some-by