JavaScript object deep comparison. Comparing x === y, where x and y are values, return true or false. Comparing x === y, where x and y are objects, returns true if x and y refer to the same object. Otherwise, returns false even if the objects appear identical. Here is a solution to check if two objects are the same.

1_primitive_comparison.js

//Primitive Type Comparison
var a = 1;
var b = 1;
var c = a;

console.log(a == b);  //true
console.log(a === b); //true
console.log(a == c);  //true
console.log(a === c); //true

2_obeject_comparison.js

//Object comparison
var a = { blah: 1 };
var b = { blah: 1 };
var c = a;

console.log(a == b);    //false
console.log(a === b);   //false
console.log(a == c);	  //true
console.log(a === c);   //true

object.compare.js

//How To Compare Object Values
var a = { blah: 1 };
var b = { blah: 1 };
var c = a;
var d = { blah: 2 };

Object.compare = function (obj1, obj2) {
	//Loop through properties in object 1
	for (var p in obj1) {
		//Check property exists on both objects
		if (obj1.hasOwnProperty(p) !== obj2.hasOwnProperty(p)) return false;
 
		switch (typeof (obj1[p])) {
			//Deep compare objects
			case 'object':
				if (!Object.compare(obj1[p], obj2[p])) return false;
				break;
			//Compare function code
			case 'function':
				if (typeof (obj2[p]) == 'undefined' || (p != 'compare' && obj1[p].toString() != obj2[p].toString())) return false;
				break;
			//Compare values
			default:
				if (obj1[p] != obj2[p]) return false;
		}
	}
 
	//Check object 2 for any extra properties
	for (var p in obj2) {
		if (typeof (obj1[p]) == 'undefined') return false;
	}
	return true;
};

console.log(Object.compare(a, b));  //true
console.log(Object.compare(a, c));  //true
console.log(Object.compare(a, d));  //false

+1 like on the solution of @DLiblik posted above, which also covers dates and functions. Maybe post it in a separate github repository so it can be found more easily?

@edwinro - done - find the gist here: areEquivalent.js

Covers most cases (including the order of the key property if present)

function isEqual(obj1, obj2) {
  function getType(obj) {
    return Object.prototype.toString.call(obj).slice(8, -1).toLowerCase();
  }

  let type = getType(obj1);

  // If the two items are not the same type, return false
  if (type !== getType(obj2)) return false;
  if (type === "array") return areArraysEqual();
  if (type === "object") return areObjectsEqual();
  if (type === "function") return areFunctionsEqual();

  function areArraysEqual() {
    // Check length
    if (obj1.length !== obj2.length) return false;
    // Check each item in the array
    for (let i = 0; i < obj1.length; i++) {
      if (!isEqual(obj1[i], obj2[i])) return false;
    }
    // If no errors, return true
    return true;
  }
  function areObjectsEqual() {
    if (Object.keys(obj1).length !== Object.keys(obj2).length) return false;
    // Check each item in the object
    for (let key in obj1) {
      if (Object.prototype.hasOwnProperty.call(obj1, key)) {
        if (!isEqual(obj1[key], obj2[key])) return false;
      }
    }
    // If no errors, return true
    return true;
  }
  function areFunctionsEqual() {
    return obj1.toString() === obj2.toString();
  }
  function arePrimativesEqual() {
    return obj1 === obj2;
  }
  return arePrimativesEqual();
}