Package Exports

@stdlib/utils-constant-function
@stdlib/utils-constant-function/lib/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@stdlib/utils-constant-function) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

Constant Function

Constant function.

A constant function is a function whose output value is the same for every input value.

Installation

npm install @stdlib/utils-constant-function

Usage

var constantFunction = require( '@stdlib/utils-constant-function' );

constantFunction( x )

Returns a constant function which always returns x.

var fcn = constantFunction( 'beep' );
// returns <Function>

var v = fcn();
// returns 'beep'

v = fcn();
// returns 'beep'

Notes

When provided an object reference, the returned function always returns the same reference.

var obj = {};
var fcn = constantFunction( obj );

var bool = ( fcn() === obj );
// returns true

Examples

var constantFunction = require( '@stdlib/utils-constant-function' );

var bool;
var fcn;
var arr;
var v;
var i;

fcn = constantFunction( 3.14 );
for ( i = 0; i < 10; i++ ) {
    v = fcn();
    // returns 3.14
}

arr = [ 1, 2, 3 ];
fcn = constantFunction( arr );
for ( i = 0; i < 10; i++ ) {
    v = fcn();
    bool = ( v === arr );
    // returns true
}

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

License

See LICENSE.

@stdlib/utils-constant-function