get difference between two arrays (including duplicates)

Question

I see a lot of posts about how to get the difference and symmetric difference of an array in javascript, but I haven\'t found anything on how to find the difference, includi

Answer 1

    Array.prototype.Diff = function( secondArray ) {
    var mergedArray = this.concat( secondArray );
    var mergedString = mergedArray.toString();
    var finalArray = new Array();

    for( var i = 0; i < mergedArray.length; i++ ) {
        if(mergedString.match(mergedArray[i])) {
            finalArray.push(mergedArray[i]);
            mergedString = mergedString.replace(new RegExp(mergedArray[i], "g"), "");
        }
    }
    return finalArray;
}

var let = [ 1 ];
var updated = [ 1, 1, 2 ];

console.log(let.Diff(updated));

I like the prototype way. You can save the prototype function above in a JS file and import in any page that you want, the it's possible to use as an embedded function to the object (Array for this case).