Question

I have developed this method which compares 2 (or more) arrays, and returns whatever you wish as result.

This is done by converting the arrays to strings then comparing them, then converting back the result. (could also be used for other stuff) instead of just doing deep iterations and recursions to do the same thing..

example:

var arr1 = [[8,0,3,0,0,7,0,9,0],[0,9,0,0,3,0,0,0,0],[0,0,0,0,0,0,4,0,6],[0,0,0,0,3,9,7,6,0],[9,6,0,5,0,7,0,8,1],[0,7,4,6,8,0,0,0,0],[5,0,1,0,0,0,0,0,0],[0,0,0,0,5,0,0,7,0],[0,6,0,7,0,0,1,0,8]];
var arr2 = [[8,7,3,0,0,7,0,9,0],[0,9,0,0,3,0,0,0,0],[0,0,0,0,0,0,4,0,6],[0,0,0,0,3,9,7,6,0],[9,6,0,5,0,7,0,8,1],[0,6,4,6,8,0,0,0,0],[5,0,1,0,0,0,0,0,0],[0,0,0,0,5,0,3,7,0],[1,6,0,7,0,0,1,0,8]];

arr1 = JSON.stringify( arr1 );
arr2 = JSON.stringify( arr2 );
var temp = ''; // this object will hold the XOR result

console.log( arr1 );
console.log( arr2 );

for( var i=0; i < arr1.length; i++ ){
    if( arr1[i] == '[' || arr1[i] == ']' || arr1[i] == ',' )
        temp += arr1[i];
    else
        temp += arr1[i] == arr2[i] ? 0 : 1;
}

console.log( temp );

what are your thoughts of this method? better for performance I believe.

Answer 1

Here’s a version that works for any type of object:

var arr1 = [[8,0,3,0,0,7,0,9,0],[0,9,0,0,3,0,0,0,0],[0,0,0,0,0,0,4,0,6],[0,0,0,0,3,9,7,6,0],[9,6,0,5,0,7,0,8,1],[0,7,4,6,8,0,0,0,0],[5,0,1,0,0,0,0,0,0],[0,0,0,0,5,0,0,7,0],[0,6,0,7,0,0,1,0,8]];
var arr2 = [[8,0,3,0,0,7,0,9,0],[0,9,0,0,3,0,0,0,0],[0,0,0,0,0,0,4,0,6],[0,0,0,0,3,9,7,6,0],[9,6,0,5,0,7,0,8,1],[0,7,4,6,8,0,0,0,0],[5,0,1,0,0,0,0,0,0],[0,0,0,0,5,0,0,7,0],[0,6,0,7,0,0,1,0,8]];

alert(isEqual(arr1, arr2));

function isEqual(obj1, obj2) {
    //make sure all keys are the same from obj1 -> obj2
    for (var key in obj1) {
        if (obj1[key] && ! obj2[key]) {
            return false;
        }
    }

    //make sure all keys are the same from obj2 -> obj1
    for (var key in obj2) {
        if (obj2[key] && ! obj1[key]) {
            return false;
        }
    }

    //make sure the key values themselves match
    for (var key in obj1) {
        var left = obj1[key];
        var right = obj2[key];
        if (left instanceof Function) {
            //don't compare these
            continue;
        } 
        if (left instanceof Object || left instanceof Array){
            if (! isEqual(left, right)) {
                return false;
            }
        }
        else if (left != right) {
            return false;
        }
    }

    return true;
}

Or if you want to list the locations of all the differences, you can use something like:

var arr1 = [[8,0,3,0,0,7,0,9,0],[0,9,0,0,3,0,0,0,0],[0,0,0,0,0,0,4,0,6],[0,0,0,0,3,9,7,6,0],[9,6,0,5,0,7,0,8,1],[0,7,4,6,8,0,0,0,0],[5,0,1,0,0,0,0,0,0],[0,0,0,0,5,0,0,7,0],[0,6,0,7,0,0,1,0,8]];
var arr2 = [[8,0,3,0,0,7,0,9,0],[0,9,0,0,3,0,0,0,0],[1,0,0,0,1,1,4,0,6],[0,0,0,0,3,9,7,6,0],[9,6,0,5,0,7,0,8,1],[0,7,4,6,8,0,0,0,0],[5,0,1,0,0,0,0,0,0],[0,0,0,0,5,0,0,7,0],[0,6,0,7,0,0,1,0,8]];

alert(listDifferences(arr1, arr2));

function listDifferences(obj1, obj2, deltaList, keyPath) {
    if (! deltaList) {
        deltaList = [];
        keyPath = "";
    }
    //make sure all keys are the same from obj1 -> obj2
    for (var key in obj1) {
        if (obj1[key] && ! obj2[key]) {
            deltaList.push("obj1" + keyPath + "[" + key + "]");
        }
    }

    //make sure all keys are the same from obj2 -> obj1
    for (var key in obj2) {
        if (obj2[key] && ! obj1[key]) {
            deltaList.push("obj2" + keyPath + "[" + key + "]");
        }
    }

    //make sure the key values themselves match
    for (var key in obj1) {
        var left = obj1[key];
        var right = obj2[key];
        if (left instanceof Function) {
            //don't compare these
            continue;
        } 
        if (left instanceof Object || left instanceof Array){
            var startingLength = deltaList.length
            if (listDifferences(left, right, deltaList, keyPath + "[" + key + "]").length > startingLength) {
                deltaList.push("obj1" + keyPath + "[" + key + "]");
            }
        }
        else if (left != right) {
            deltaList.push("obj1" + keyPath + "[" + key + "]");
        }
    }

    return deltaList;
}