Get version number from String in Javascript?

Question

I have a version number with 3 digits as a String,

var version = "1.2.3";

and would like to compare it to another version. To see if version is newer than otherversion,

var otherVersion = "1.2.4";

How would you do it?

Answer 1

With one of the comparison operators.

"1.2.3" > "1.2.4" //false

"1.2.3" < "1.2.4" //true

Answer 2

Pseudo:

• Split both on .
• Compare parts sequentially: Major -> Minor -> Rev (if part exist for both versions).
• If oV[n] > v[n]: oV is greatest.
• Else: Compare next subpart.

(See @arhorns answer for a elegant implementation)

Answer 3

If indeed you only have a single digit in each part why not just use straight comparison?

>>> var version = "1.2.3"; var otherVersion = "1.2.4"; version < otherVersion
true

It seems also to work with abbreviated versions:

>>> '1.2' > '1.2.4'
false
>>> '1.3' > '1.2.4'
true

Answer 4

function VersionValue(var str)
{
var tmp = str.split('.');
return (tmp[0] * 100) + (tmp[1] * 10) + tmp[2];
}

if (VersionValue(version) > VersionValue(otherVersion))...

for example

Answer 5

You may want to use the following implementation (based on jensgram's solution):

function isNewer(a, b) {
   var partsA = a.split('.');
   var partsB = b.split('.');
   var numParts = partsA.length > partsB.length ? partsA.length : partsB.length;
   var i;

   for (i = 0; i < numParts; i++) {
      if ((parseInt(partsB[i], 10) || 0) !== (parseInt(partsA[i], 10) || 0)) {
         return ((parseInt(partsB[i], 10) || 0) > (parseInt(partsA[i], 10) || 0));
      }
   }

   return false;
}

console.log(isNewer('1.2.3', '1.2.4'));    // true
console.log(isNewer('1.2.3', '1.2.0'));    // false
console.log(isNewer('1.2.3', '1.2.3.1'));  // true
console.log(isNewer('1.2.3', '1.2.2.9'));  // false
console.log(isNewer('1.2.3', '1.2.10'));   // true

Note that the use of parseInt() is necessary, because otherwise the last test would return false: "10" > "3" returns false.

Answer 6

Maybe like this (quickie)?

function isNewer(s0, s1) {
    var v0 = s0.split('.'), v1 = s1.split('.');
    var len0 = v0.length, len1=v1.length;
    var temp0, temp1, idx = 0;
    while (idx<len0) {
        temp0 = parseInt(v0[idx], 10);
        if (len1>idx) {
            temp1 = parseInt(v1[idx], 10);
            if (temp1>temp0) {return true;}
        }
        idx += 1;
    }
    if (parseInt(v0[idx-1], 10)>parseInt(v1[idx-1], 10)) {return false;}
    return len1 > len0;
}
var version = "1.2.3";
var otherVersion = "1.2.4";

console.log('newer:'+(isNewer(version, otherVersion)));

It takes care of different number of parts, but it works only with numbers between the dots though.

Answer 7

The problem with most of the submitted versions is they can't handle any number of version parts (eg. 1.4.2 .. 1.2 etc) and/or they have the requirement of the version part being a single digit, which is not that common actually.

Improved compareVersions() function

This function will return 1 if v1 is greater than v2, -1 if v2 is greater and 0 if the versions are equal (handy for custom sorting as well)

I'm not doing any error checking on the inputs.

function compareVersions (v1, v2)
{
    v1 = v1.split('.');
    v2 = v2.split('.');
    var longestLength = (v1.length > v2.length) ? v1.length : v2.length;
    for (var i = 0; i < longestLength; i++) {
        if (v1[i] != v2[i]) {
            return (v1 > v2) ? 1 : -1
        }
    }
    return 0; 
 }

Answer 8

Since I'm bored, here's an approach similar to our decimal system (tens, hundreds, thousands, etc) which uses a regex callback instead of a loop:

function compareVersion(a, b) {
    var expr = /\d+/g, places = Math.max(a.split(expr).length, b.split(expr).length);
    function convert(s) {
        var place = Math.pow(100, places), total = 0;
        s.replace(expr,
            function (n) {
                total += n * place;
                place /= 100;
            }
        );
        return total;
    };

    if (convert(a) > convert(b)) {
        return a;
    }

    return b;
}

It returns the greater version, e.g.:

compareVersion('1.4', '1.3.99.32.60.4'); // => 1.4

Answer 9

Note, that none of these solutions will knowingly return the right result for things like 0.9beta or 1.0 RC 1. It is, however, handled quite intuitively in PHP: http://de3.php.net/manual/en/function.version-compare.php and there is a JS port of this: http://phpjs.org/functions/version_compare (I don't claim this to be very nice or efficient, just kind of 'complete').