Test if a value is an arrow function.
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> Test if a value is an [arrow function][mdn-arrow-function].
``bash`
npm install @stdlib/assert-is-arrow-function
`javascript`
var isArrowFunction = require( '@stdlib/assert-is-arrow-function' );
#### isArrowFunction( value )
Tests if a value is an [arrow function][mdn-arrow-function] such as ( a, b ) => a + b, x => x, or ( x ) => { return x*x; }.
`javascript
var beep = () => {
console.log( 'beep' );
};
var bool = isArrowFunction( beep );
// returns true
function boop() {
console.log( 'boop' );
}
bool = isArrowFunction( boop );
// returns false
`
`javascript
var isArrowFunction = require( '@stdlib/assert-is-arrow-function' );
var bool = isArrowFunction( () => {} );
// returns true
bool = isArrowFunction( function foo() {} );
// returns false
bool = isArrowFunction( 'beep' );
// returns false
bool = isArrowFunction( 5 );
// returns false
bool = isArrowFunction( true );
// returns false
bool = isArrowFunction( null );
// returns false
bool = isArrowFunction( [] );
// returns false
bool = isArrowFunction( {} );
// returns false
`
*
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].
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---
See [LICENSE][stdlib-license].
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
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[npm-url]: https://npmjs.org/package/@stdlib/assert-is-arrow-function
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[test-url]: https://github.com/stdlib-js/assert-is-arrow-function/actions/workflows/test.yml?query=branch:v0.2.4
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/assert-is-arrow-function/main.svg
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[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/assert-is-arrow-function/tree/deno
[deno-readme]: https://github.com/stdlib-js/assert-is-arrow-function/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/assert-is-arrow-function/tree/umd
[umd-readme]: https://github.com/stdlib-js/assert-is-arrow-function/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/assert-is-arrow-function/tree/esm
[esm-readme]: https://github.com/stdlib-js/assert-is-arrow-function/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/assert-is-arrow-function/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/assert-is-arrow-function/main/LICENSE
[mdn-arrow-function]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions