Get the property of the difference between two objects in javascript

Question

Let's say that I have an object which looks like this:

{
  prop1: false,
  prop2: false,
  prop3: false
}

and another object which looks like this:

{
  prop1: false,
  prop2: true,
  prop3: false
}

where the difference is within the prop2 property. Is there any way or library (vanilla preferred though) which will compare the two objects, find the property with the different value, and return the property name (in this case prop2)?

I have tried using the difference and differenceBy functions in lodash to no success. Any help or suggestions will be greatly appreciated!

Answer 1

You could filter the keys (assuming same keys) by checking the unequal value.

var obj1 = { prop1: false, prop2: false, prop3: false },
    obj2 = { prop1: false, prop2: true, prop3: false },
    difference = Object.keys(obj1).filter(k => obj1[k] !== obj2[k]);
    
console.log(difference);

Answer 2

This function will extract all the difference between two objects. It will also works on nested objects. This code uses some lodash functions. (function names that starts with "_.")

function difference(object, base) {
    function changes(object, base) {
        return _.transform(object, function(result, value, key) {
            if (!_.isEqual(value, base[key])) {
                result[key] = (_.isObject(value) && _.isObject(base[key])) ? changes(value, base[key]) : value;
            }
        });
    }
    return changes(object, base);
}