jQuery/JavaScript JSON object comparison

Question

Is it possible to compare 2 sets of json objects for a difference? What I have is a script thats polling for JSON object via jquery $post(). What I want to do is take the ob

Answer 1

Here is my code:

    function getDifferences(oldObj, newObj) {
    var diff = {};

    for (var k in oldObj) {
        if (!(k in newObj)){
            diff[k] = undefined;  // old key does not exist in new
        } else {
            switch (typeof oldObj[k]){
                case "array": {
                    String(oldObj[k]) !== String(newObj[k]) ? diff[k] = newObj[k] : null;
                    break;
                } case "object": {                        
                    Object.keys(oldObj[k]).forEach(key =>{                           
                        if(oldObj[k][key] !== newObj[k][key]){
                            if(diff[k]){
                                diff[k][key] = newObj[k][key];
                            } else {
                                diff[k] = {[key]: newObj[k][key]}
                            }
                        }
                    });
                    //JSON.stringify(oldObj[k]) !== JSON.stringify(newObj[k]) ? diff[k] = newObj[k] : null; Optional basic comparision
                    break;
                } default: { //Values are strings or numbers
                    oldObj[k] !== newObj[k] ? diff[k] = newObj[k] : null;
                    break;
                }
            }
        }
    }

    for (k in newObj) {
        if (!(k in oldObj))
        diff[k] = newObj[k]; // property is new
    }     
    return diff;
}

We get the type of the elements and make an internal comparision of equality.