# Function Name [![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] > [Regular expression][regexp] to capture a function name.
## Installation ```bash npm install @stdlib/regexp-function-name ```
## Usage ```javascript var reFunctionName = require( '@stdlib/regexp-function-name' ); ``` #### reFunctionName Returns a [regular expression][regexp] to capture a `function` name. ```javascript function beep() { return 'boop'; } var RE_FUNCTION_NAME = reFunctionName(); var str = RE_FUNCTION_NAME.exec( beep.toString() )[ 1 ]; // returns 'beep' ``` #### reFunctionName.REGEXP [Regular expression][regexp] to capture a `function` name. ```javascript var str = reFunctionName.REGEXP.exec( Math.sqrt.toString() )[ 1 ]; // returns 'sqrt' ```
## Examples ```javascript var Int8Array = require( '@stdlib/array-int8' ); var reFunctionName = require( '@stdlib/regexp-function-name' ); var RE_FUNCTION_NAME = reFunctionName(); function fname( fcn ) { return RE_FUNCTION_NAME.exec( fcn.toString() )[ 1 ]; } var f = fname( Math.sqrt ); // returns 'sqrt' f = fname( Int8Array ); // returns 'Int8Array' f = fname( Object.prototype.toString ); // returns 'toString' f = fname( function () {} ); // returns '' ```
* * * ## 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 © 2016-2022. The Stdlib [Authors][stdlib-authors].