PHP's call_user_func_array in JavaScript

Here’s what our current JavaScript equivalent to PHP's call_user_func_array looks like.

module.exports = function call_user_func_array (cb, parameters) { // eslint-disable-line camelcase
// discuss at:
// original by: Thiago Mata (
// revised by: Jon Hohle
// improved by: Brett Zamir (
// improved by: Diplom@t (
// improved by: Brett Zamir (
// note 1: Depending on the `cb` that is passed,
// note 1: this function can use `eval` and/or `new Function`.
// note 1: The `eval` input is however checked to only allow valid function names,
// note 1: So it should not be unsafer than uses without eval (seeing as you can)
// note 1: already pass any function to be executed here.
// example 1: call_user_func_array('isNaN', ['a'])
// returns 1: true
// example 2: call_user_func_array('isNaN', [1])
// returns 2: false
const $global = (typeof window !== 'undefined' ? window : global)
let func
let scope = null
const validJSFunctionNamePattern = /^[_$a-zA-Z\xA0-\uFFFF][_$a-zA-Z0-9\xA0-\uFFFF]*$/
if (typeof cb === 'string') {
if (typeof $global[cb] === 'function') {
func = $global[cb]
} else if (cb.match(validJSFunctionNamePattern)) {
func = (new Function(null, 'return ' + cb)()) // eslint-disable-line no-new-func
} else if ( === '[object Array]') {
if (typeof cb[0] === 'string') {
if (cb[0].match(validJSFunctionNamePattern)) {
func = eval(cb[0] + "['" + cb[1] + "']") // eslint-disable-line no-eval
} else {
func = cb[0][cb[1]]
if (typeof cb[0] === 'string') {
if (typeof $global[cb[0]] === 'function') {
scope = $global[cb[0]]
} else if (cb[0].match(validJSFunctionNamePattern)) {
scope = eval(cb[0]) // eslint-disable-line no-eval
} else if (typeof cb[0] === 'object') {
scope = cb[0]
} else if (typeof cb === 'function') {
func = cb
if (typeof func !== 'function') {
throw new Error(func + ' is not a valid function')
return func.apply(scope, parameters)
[ View on GitHub | Edit on GitHub | Source on GitHub ]

How to use

You you can install via npm install locutus and require it via require('locutus/php/funchand/call_user_func_array'). You could also require the funchand module in full so that you could access funchand.call_user_func_array instead.

If you intend to target the browser, you can then use a module bundler such as Parcel, webpack, Browserify, or rollup.js. This can be important because Locutus allows modern JavaScript in the source files, meaning it may not work in all browsers without a build/transpile step. Locutus does transpile all functions to ES5 before publishing to npm.

A community effort

Not unlike Wikipedia, Locutus is an ongoing community effort. Our philosophy follows The McDonald’s Theory. This means that we don't consider it to be a bad thing that many of our functions are first iterations, which may still have their fair share of issues. We hope that these flaws will inspire others to come up with better ideas.

This way of working also means that we don't offer any production guarantees, and recommend to use Locutus inspiration and learning purposes only.


  • Depending on the cb that is passed, this function can use eval and/or new Function. The eval input is however checked to only allow valid function names, So it should not be unsafer than uses without eval (seeing as you can) already pass any function to be executed here.


Please note that these examples are distilled from test cases that automatically verify our functions still work correctly. This could explain some quirky ones.

#codeexpected result
1call_user_func_array('isNaN', ['a'])true
2call_user_func_array('isNaN', [1])false

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