JavaScript strrev

Reverse a string

function strrev (string) {
    // Reverse a string  
    // 
    // version: 912.1315
    // discuss at: http://phpjs.org/functions/strrev    // +   original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +   bugfixed by: Onno Marsman
    // +   reimplemented by: Brett Zamir (http://brett-zamir.me)
    // *     example 1: strrev('Kevin van Zonneveld');
    // *     returns 1: 'dlevennoZ nav niveK'    // *     example 2: strrev('a\u0301haB') === 'Baha\u0301'; // combining
    // *     returns 2: true
    // *     example 3: strrev('A\uD87E\uDC04Z') === 'Z\uD87E\uDC04A'; // surrogates
    // *     returns 2: true
    string = string+''; 
    // Performance will be enhanced with the next two lines of code commented
    //      out if you don't care about combining characters
    // Keep Unicode combining characters together with the character preceding
    //      them and which they are modifying (as in PHP 6)    // See http://unicode.org/reports/tr44/#Property_Table (Me+Mn)
    // We also add the low surrogate range at the beginning here so it will be
    //      maintained with its preceding high surrogate
    var grapheme_extend = /(.)([\uDC00-\uDFFF\u0300-\u036F\u0483-\u0489\u0591-\u05BD\u05BF\u05C1\u05C2\u05C4\u05C5\u05C7\u0610-\u061A\u064B-\u065E\u0670\u06D6-\u06DC\u06DE-\u06E4\u06E7\u06E8\u06EA-\u06ED\u0711\u0730-\u074A\u07A6-\u07B0\u07EB-\u07F3\u0901-\u0903\u093C\u093E-\u094D\u0951-\u0954\u0962\u0963\u0981-\u0983\u09BC\u09BE-\u09C4\u09C7\u09C8\u09CB-\u09CD\u09D7\u09E2\u09E3\u0A01-\u0A03\u0A3C\u0A3E-\u0A42\u0A47\u0A48\u0A4B-\u0A4D\u0A51\u0A70\u0A71\u0A75\u0A81-\u0A83\u0ABC\u0ABE-\u0AC5\u0AC7-\u0AC9\u0ACB-\u0ACD\u0AE2\u0AE3\u0B01-\u0B03\u0B3C\u0B3E-\u0B44\u0B47\u0B48\u0B4B-\u0B4D\u0B56\u0B57\u0B62\u0B63\u0B82\u0BBE-\u0BC2\u0BC6-\u0BC8\u0BCA-\u0BCD\u0BD7\u0C01-\u0C03\u0C3E-\u0C44\u0C46-\u0C48\u0C4A-\u0C4D\u0C55\u0C56\u0C62\u0C63\u0C82\u0C83\u0CBC\u0CBE-\u0CC4\u0CC6-\u0CC8\u0CCA-\u0CCD\u0CD5\u0CD6\u0CE2\u0CE3\u0D02\u0D03\u0D3E-\u0D44\u0D46-\u0D48\u0D4A-\u0D4D\u0D57\u0D62\u0D63\u0D82\u0D83\u0DCA\u0DCF-\u0DD4\u0DD6\u0DD8-\u0DDF\u0DF2\u0DF3\u0E31\u0E34-\u0E3A\u0E47-\u0E4E\u0EB1\u0EB4-\u0EB9\u0EBB\u0EBC\u0EC8-\u0ECD\u0F18\u0F19\u0F35\u0F37\u0F39\u0F3E\u0F3F\u0F71-\u0F84\u0F86\u0F87\u0F90-\u0F97\u0F99-\u0FBC\u0FC6\u102B-\u103E\u1056-\u1059\u105E-\u1060\u1062-\u1064\u1067-\u106D\u1071-\u1074\u1082-\u108D\u108F\u135F\u1712-\u1714\u1732-\u1734\u1752\u1753\u1772\u1773\u17B6-\u17D3\u17DD\u180B-\u180D\u18A9\u1920-\u192B\u1930-\u193B\u19B0-\u19C0\u19C8\u19C9\u1A17-\u1A1B\u1B00-\u1B04\u1B34-\u1B44\u1B6B-\u1B73\u1B80-\u1B82\u1BA1-\u1BAA\u1C24-\u1C37\u1DC0-\u1DE6\u1DFE\u1DFF\u20D0-\u20F0\u2DE0-\u2DFF\u302A-\u302F\u3099\u309A\uA66F-\uA672\uA67C\uA67D\uA802\uA806\uA80B\uA823-\uA827\uA880\uA881\uA8B4-\uA8C4\uA926-\uA92D\uA947-\uA953\uAA29-\uAA36\uAA43\uAA4C\uAA4D\uFB1E\uFE00-\uFE0F\uFE20-\uFE26])/g;
    string = string.replace(grapheme_extend, '$2$1'); // Temporarily reverse 
    return string.split('').reverse().join('');
}

external links: original PHP docs | raw js source

Examples

» Example 1

Running

1	strrev('Kevin van Zonneveld');

Should return

1	'dlevennoZ nav niveK'

» Example 2

Running

1	strrev('a\u0301haB') === 'Baha\u0301'; // combining

Should return

true

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 strrev goodness in JavaScript.

Kevin van Zonneveld ( original )
Onno Marsman ( bugfixed )
Brett Zamir ( reimplemented )

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

Kevin van Zonneveld
19 Jan '08

@ Legaev Andrey: wicked :)

Legaev Andrey
19 Jan '08

Ajaxian replacements of file_get_contents() and file():

function file_get_contents(url) {
        // +    original by: Legaev Andrey
        // *    note:   Whis function uses XmlHttpRequest and cannot retrieve resource from different domain.
        var req = null;
        try { req = new ActiveXObject(&quot;Msxml2.XMLHTTP&quot;); } catch (e) {                try { req = new ActiveXObject(&quot;Microsoft.XMLHTTP&quot;); } catch (e) {
                        try { req = new XMLHttpRequest(); } catch(e) {}
                }
        }
        if (req == null) throw new Error('XMLHttpRequest not supported');        
        req.open(&quot;GET&quot;, url, false);
        req.send(null);
 
        return req.responseText;}
 
function file(url) {
        // +    original by: Legaev Andrey
        // *    note:   Whis function uses XmlHttpRequest and cannot retrieve resource from different domain.        var req = null;
        try { req = new ActiveXObject(&quot;Msxml2.XMLHTTP&quot;); } catch (e) {
                try { req = new ActiveXObject(&quot;Microsoft.XMLHTTP&quot;); } catch (e) {
                        try { req = new XMLHttpRequest(); } catch(e) {}
                }        }
        if (req == null) throw new Error('XMLHttpRequest not supported');
        
        req.open(&quot;GET&quot;, url, false);
        req.send(null); 
        return req.responseText.split('\n');
}

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