DeepObjectComparison.js

private difference(object1, object2) {
    if (!object2 || Object.prototype.toString.call(object2) !== '[object Object]') {
      return object1;
    }

    const differences = {};
    let key;
    
    const arraysMatch = (array1, array2) => {
      if (array1.length !== array2.length) return false;

      for (let i = 0; i < array1.length; i++) {
        if (array1[i] !== array2[i]) return false;
      }

      return true;
    };

    const compare = (item1, item2, compareKey) => {
      const type1 = Object.prototype.toString.call(item1);
      const type2 = Object.prototype.toString.call(item2);

      if (type2 === '[object Undefined]') {
        differences[compareKey] = null;
        return;
      }

      if (type1 !== type2) {
        differences[compareKey] = item2;
        return;
      }

      if (type1 === '[object Object]') {
        const objectDifference = this.difference(item1, item2);
        if (Object.keys(objectDifference).length > 1) {
          differences[compareKey] = objectDifference;
        }
        return;
      }

      if (type1 === '[object Array]') {
        if (!arraysMatch(item1, item2)) {
          differences[compareKey] = item2;
        }
        return;
      }

      if (type1 === '[object Function]') {
        if (item1.toString() !== item2.toString()) {
          differences[compareKey] = item2;
        }
      } else {
        if (item1 !== item2 ) {
          differences[compareKey] = item2;
        }
      }

    };

    for (key in object1) {
      if (object1.hasOwnProperty(key)) {
        compare(object1[key], object2[key], key);
      }
    }

    for (key in object2) {
      if (object2.hasOwnProperty(key)) {
        if (!object1[key] && object1[key] !== object2[key] ) {
          differences[key] = object2[key];
        }
      }
    }

    return differences;
  };