JavaScript array_keys

Return just the keys from the input array, optionally only for the specified search_value

function array_keys (input, search_value, argStrict) {
    // Return just the keys from the input array, optionally only for the specified search_value  
    // 
    // version: 1109.2015
    // discuss at: http://phpjs.org/functions/array_keys    // +   original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +      input by: Brett Zamir (http://brett-zamir.me)
    // +   bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +   improved by: jd
    // +   improved by: Brett Zamir (http://brett-zamir.me)    // +   input by: P
    // +   bugfixed by: Brett Zamir (http://brett-zamir.me)
    // *     example 1: array_keys( {firstname: 'Kevin', surname: 'van Zonneveld'} );
    // *     returns 1: {0: 'firstname', 1: 'surname'}
    var search = typeof search_value !== 'undefined',        tmp_arr = [],
        strict = !!argStrict,
        include = true,
        key = '';
     if (input && typeof input === 'object' && input.change_key_case) { // Duck-type check for our own array()-created PHPJS_Array
        return input.keys(search_value, argStrict);
    }
 
    for (key in input) {        if (input.hasOwnProperty(key)) {
            include = true;
            if (search) {
                if (strict && input[key] !== search_value) {
                    include = false;                }
                else if (input[key] != search_value) {
                    include = false;
                }
            } 
            if (include) {
                tmp_arr[tmp_arr.length] = key;
            }
        }    }
 
    return tmp_arr;
}

external links: original PHP docs | raw js source

Examples

Running

1	array_keys( {firstname: 'Kevin', surname: 'van Zonneveld'} );

Should return

1	{0: 'firstname', 1: 'surname'}

Dependencies

No dependencies, you can use this function standalone.

Open syntax issues

php.js uses JsLint to help us keep our code consistent and prevent some common bugs.

Eventually we want all code to pass or at least take into consideration most fixes suggested by JsLint, following this JsLint configuration we’ve decided on.

Authors

Thanks to the following developers, you get to have array_keys goodness in JavaScript.

Kevin van Zonneveld ( original bugfixed )
Brett Zamir ( input bugfixed improved )
P ( input )
jd ( improved )

Comments

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Use:

[CODE]
your_stuff('here');
[/CODE]

for proper code formatting
By submitting code here you are allowing us to use it in php.js hence dual licensing it under the MIT and GPL licenses

بوابة نعم
Apr 4th

I have a lot to benefit from this article and thank you for this wonderful effort to this article and will continue my many articles you have other

Brett Zamir
13 Jun '11

@P: Fixed in Git. Thanks for the report!

P
12 Jun '11

The raw seems to be different than the site's copy, and in the raw copy there's a cs variable that's unaccounted for.

Brett Zamir
18 Feb '11

@jd: Yes, in this function, I see no reason we shouldn't return a genuine array, since PHP is not preserving keys of an original array here but is just starting fresh (and is only producing a sequential numeric array). I've fixed in Git. Some of our other functions, however, our constrained to return an object in order to preserve keys and/or to avoid returning confusing arrays which have "undefined" interspersed throughout.

jd
16 Feb '11

Shouldn't line 11 be:

var tmp_arr = []
(i.e. not curly brackets)

Brett Zamir
12 May '10

@JeromeM: Can you provide some sample data where it is not working? Are you using the latest version? (see "raw js source" link on this page) What errors? The example is working for me

JeromeM
12 May '10

Doesn't seem to work on Safari 4 ..
Neither on Safari 3.x (i'm actually developping for iPhone / iPad).

Brett Zamir
12 Jan '10

Hello Mickael,

This should definitely be working in Firefox, as that is what i use to test it. Can you please give example code which causes the problem for you? Are you using any other libraries with your code like Prototype?

Mickael
12 Jan '10

Hi,
I test this function with Mozilla Firefox 3.5.7 but it does not work.
I think that Mozilla has a bug concerning "for in" syntax.

Thanks for all scripts, PHP.JS is a very good work :)

Kevin van Zonneveld
22 Jan '08

@ Ates Goral: Nice work, added!

Ates Goral
22 Jan '08

Hmmm. I should change that to:

[CODE="Javascript"]
const CASE_LOWER = 0;
const CASE_UPPER = 1;
[/CODE]

Ates Goral
22 Jan '08

Hey Kevin, here's my implementation for array_change_key_case().

[CODE="Javascript"]
var CASE_LOWER = 0;
var CASE_UPPER = 1;

function array_change_key_case(array) {
// * example 1: array_change_key_case(42);
// * returns 1: false
// * example 2: array_change_key_case([ 3, 5 ]);
// * returns 2: {0: 3, 1: 5}
// * example 3: array_change_key_case({ FuBaR: 42 });
// * returns 3: {"fubar": 42}
// * example 4: array_change_key_case({ FuBaR: 42 }, CASE_LOWER);
// * returns 4: {"fubar": 42}
// * example 5: array_change_key_case({ FuBaR: 42 }, CASE_UPPER);
// * returns 5: {"FUBAR": 42}
// * example 6: array_change_key_case({ FuBaR: 42 }, 2);
// * returns 6: {"FUBAR": 42}

if (array instanceof Array) {
return array;
}

if (array instanceof Object) {
var case_fn = (arguments.length == 1 || arguments[1] == CASE_LOWER) ?
"toLowerCase" : "toUpperCase";
var ret = new Object();

for (var key in array) {
ret[key[case_fn]()] = array[key];
}

return ret;
}

return false;
}
[/CODE]

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