Is There a Javascript Strcmp()?

Can anyone verify this for me? JavaScript does not have a version of strcmp(), so you have to write out something like:

 ( str1 < str2 ) ? 
            -1 : 
             ( str1 > str2 ? 1 : 0 );
1

6 Answers

What about

str1.localeCompare(str2)
6

Javascript doesn't have it, as you point out.

A quick search came up with:

function strcmp ( str1, str2 ) {
    // 
    // +   original by: Waldo Malqui Silva
    // +      input by: Steve Hilder
    // +   improved by: Kevin van Zonneveld ()
    // +    revised by: gorthaur
    // *     example 1: strcmp( 'waldo', 'owald' );
    // *     returns 1: 1
    // *     example 2: strcmp( 'owald', 'waldo' );
    // *     returns 2: -1

    return ( ( str1 == str2 ) ? 0 : ( ( str1 > str2 ) ? 1 : -1 ) );
}

from

Of course, you could just add localeCompare if needed:

if (typeof(String.prototype.localeCompare) === 'undefined') {
    String.prototype.localeCompare = function(str, locale, options) {
        return ((this == str) ? 0 : ((this > str) ? 1 : -1));
    };
}

And use str1.localeCompare(str2) everywhere, without having to worry wether the local browser has shipped with it. The only problem is that you would have to add support for locales and options if you care about that.

2

localeCompare() is slow, so if you don't care about the "correct" ordering of non-English-character strings, try your original method or the cleaner-looking:

str1 < str2 ? -1 : +(str1 > str2)

This is an order of magnitude faster than localeCompare() on my machine.

The + ensures that the answer is always numeric rather than boolean.

8
var strcmp = new Intl.Collator(undefined, {numeric:true, sensitivity:'base'}).compare;

Usage: strcmp(string1, string2)

Result: 1 means string1 is bigger, 0 means equal, -1 means string2 is bigger.

This has higher performance than String.prototype.localeCompare

Also, numeric:true makes it do logical number comparison

1

from this How to Check if Two Strings are Equal in JavaScript article:

  1. Generally, if your strings contain only ASCII characters, you use the === operator to check if they are equal.
  2. But when your strings contain characters that include combining characters(eg. e + ◌́ = é), you normalize them first before comparing for equality as follows- s1.normalize() === s2.normalize()

How about:

String.prototype.strcmp = function(s) {
    if (this < s) return -1;
    if (this > s) return 1;
    return 0;
}

Then, to compare s1 with 2:

s1.strcmp(s2)
2

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Sarah Jenkins

Sarah Jenkins

Senior Technology Editor & AI Specialist

Sarah Jenkins is a veteran tech journalist with over 12 years of experience covering artificial intelligence, mobile innovations, and digital ethics. Her insights have appeared in leading technology publications worldwide.

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