JavaScript strncasecmp

Binary safe string comparison

function strncasecmp (argStr1, argStr2, len) {
    // Binary safe string comparison  
    // 
    // version: 1008.1718
    // discuss at: http://phpjs.org/functions/strncasecmp    // +   original by: Saulo Vallory
    // +      input by: Nate
    // +   bugfixed by: Onno Marsman
    // %          note: Returns < 0 if str1 is less than str2 ; > 0 if str1 is greater than str2 , and 0 if they are equal.
    // *     example 1: strncasecmp('Price 12.9', 'Price 12.15', 2);    // *     returns 1: 0
    // *     example 2: strncasecmp('Price 12.09', 'Price 12.15', 10);
    // *     returns 2: -1
    // *     example 3: strncasecmp('Price 12.90', 'Price 12.15', 30);
    // *     returns 3: 8    // *     example 4: strncasecmp('Version 12.9', 'Version 12.15', 20);
    // *     returns 4: 8
    // *     example 5: strncasecmp('Version 12.15', 'Version 12.9', 20);
    // *     returns 5: -8
    var diff, i = 0;    var str1 = (argStr1+'').toLowerCase().substr(0,len);
    var str2 = (argStr2+'').toLowerCase().substr(0,len);
 
    if (str1.length !== str2.length) {
        if (str1.length < str2.length) {            len = str1.length;
            if (str2.substr(0, str1.length) == str1) {
                return str1.length - str2.length; // return the difference of chars
            }
        } else {            len = str2.length;
            // str1 is longer than str2
            if (str1.substr(0, str2.length) == str2) {
                return str1.length - str2.length; // return the difference of chars
            }        }
    } else {
        // Avoids trying to get a char that does not exist
        len = str1.length;
    } 
    for (diff = 0, i=0; i < len; i++) {
        diff = str1.charCodeAt(i) - str2.charCodeAt(i);
        if (diff !== 0) {
            return diff;        }
    }
 
    return 0;
}

external links: original PHP docs | raw js source

Examples

» Example 1

Running

1	strncasecmp('Price 12.9', 'Price 12.15', 2);

Should return

» Example 2

Running

1	strncasecmp('Price 12.09', 'Price 12.15', 10);

Should return

-1

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 strncasecmp goodness in JavaScript.

Saulo Vallory ( original )
Nate ( input )
Onno Marsman ( bugfixed )

Comments

Add Comment

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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
24 Sep '08

@ Nate: Fixed, thank you!

Nate
23 Sep '08

Slight grammar error:
// avoids trying to get a char that does not exists
should be
// avoids trying to get a char that does not exist

Also for comment:
// str1 is lengthier than str2
"longer" might be better than "lengthier"; however, that is more of an opinion.

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