PHP's array_unique in JavaScript

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

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module.exports = function array_unique (inputArr) { // eslint-disable-line camelcase
// discuss at: http://locutus.io/php/array_unique/
// original by: Carlos R. L. Rodrigues (http://www.jsfromhell.com)
// input by: duncan
// input by: Brett Zamir (http://brett-zamir.me)
// bugfixed by: Kevin van Zonneveld (http://kvz.io)
// bugfixed by: Nate
// bugfixed by: Kevin van Zonneveld (http://kvz.io)
// bugfixed by: Brett Zamir (http://brett-zamir.me)
// improved by: Michael Grier
// note 1: The second argument, sort_flags is not implemented;
// note 1: also should be sorted (asort?) first according to docs
// example 1: array_unique(['Kevin','Kevin','van','Zonneveld','Kevin'])
// returns 1: {0: 'Kevin', 2: 'van', 3: 'Zonneveld'}
// example 2: array_unique({'a': 'green', 0: 'red', 'b': 'green', 1: 'blue', 2: 'red'})
// returns 2: {a: 'green', 0: 'red', 1: 'blue'}
var key = ''
var tmpArr2 = {}
var val = ''
var _arraySearch = function (needle, haystack) {
var fkey = ''
for (fkey in haystack) {
if (haystack.hasOwnProperty(fkey)) {
if ((haystack[fkey] + '') === (needle + '')) {
return fkey
}
}
}
return false
}
for (key in inputArr) {
if (inputArr.hasOwnProperty(key)) {
val = inputArr[key]
if (_arraySearch(val, tmpArr2) === false) {
tmpArr2[key] = val
}
}
}
return tmpArr2
}
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How to use

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

If you intend to target the browser, you can then use a module bundler such as Browserify, webpack or rollup.js.

ES5/ES6

This function targets ES5, but as of Locutus 2.0.2 we also support ES6 functions. Locutus transpiles to ES5 before publishing to npm.

PHP arrays and JavaScript

Please note that Locutus uses JavaScript objects as substitutes for PHP arrays, they are the closest we can get to this hashtable-like data structure without rolling our own. While many JavaScript implementations preserve the order of object properties, the ECMAScript Language Specification explicitly states that:

The mechanics and order of enumerating the properties is not specified.

So don't use this for anything serious if you rely on the order to be consistent accross platforms.

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.

Notes

  • The second argument, sort_flags is not implemented; also should be sorted (asort?) first according to docs

Examples

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
1array_unique(['Kevin','Kevin','van','Zonneveld','Kevin']){0: 'Kevin', 2: 'van', 3: 'Zonneveld'}
2array_unique({'a': 'green', 0: 'red', 'b': 'green', 1: 'blue', 2: 'red'}){a: 'green', 0: 'red', 1: 'blue'}

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