stdlib-js / utils-function-name

Determine a function's name.

Function Name

Determine a function's name.

Installation

npm install @stdlib/utils-function-name

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch.
• If you are using Deno, visit the deno branch.
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch.

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

Usage

var functionName = require( '@stdlib/utils-function-name' );

functionName( fcn )

Returns the name of a function.

var v = functionName( Math.sqrt );
// returns 'sqrt'

If provided an anonymous function, the function returns an empty string or the string "anonymous".

var v = functionName( function () {} );
// returns '' || 'anonymous'

If provided a value which is not a function, the function throws a TypeError.

try {
    functionName( 'beep' );
    // throws error...
} catch ( err ) {
    console.error( err );
}

Notes

• For more information regarding the naming of anonymous functions, see

  • Function Names in ES6
  • Webkit bug 7726
  • MDN

Examples

var Float64Array = require( '@stdlib/array-float64' );
var Buffer = require( '@stdlib/buffer-ctor' );
var Number = require( '@stdlib/number-ctor' );
var functionName = require( '@stdlib/utils-function-name' );

var v = functionName( Math.sqrt );
// returns 'sqrt'

v = functionName( Float64Array );
// returns 'Float64Array'

v = functionName( Buffer );
// returns 'Buffer'

v = functionName( Date );
// returns 'Date'

v = functionName( String );
// returns 'String'

v = functionName( Boolean );
// returns 'Boolean'

v = functionName( Function );
// returns 'Function'

v = functionName( Number );
// returns 'Number'

v = functionName( function foo() {} );
// returns 'foo'

v = functionName( function () {} );
// returns '' || 'anonymous'

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See Also

• @stdlib/utils-constructor-name: determine the name of a value's constructor.

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Notice

This package is part of 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, see the main project repository.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2023. The Stdlib Authors.