How can I compare arbitrary version numbers?

Question

Does anyone have code to compare two version numbers in JavaScript? I just want simple version comparisons (e.g. \"1.0\" vs \"1.5.6\"), and it shou

Answer 1

function cmpVersion(a, b) {
    var i, cmp, len;
    a = (a + '').split('.');
    b = (b + '').split('.');
    len = Math.max(a.length, b.length);
    for( i = 0; i < len; i++ ) {
        if( a[i] === undefined ) {
            a[i] = '0';
        }
        if( b[i] === undefined ) {
            b[i] = '0';
        }
        cmp = parseInt(a[i], 10) - parseInt(b[i], 10);
        if( cmp !== 0 ) {
            return (cmp < 0 ? -1 : 1);
        }
    }
    return 0;
}

function gteVersion(a, b) {
    return cmpVersion(a, b) >= 0;
}
function ltVersion(a, b) {
    return cmpVersion(a, b) < 0;
}

This function handles:

• numbers or strings as input
• trailing zeros (e.g. cmpVersion("1.0", 1) returns 0)
• ignores trailing alpha, b, pre4, etc