code: function shallowEqual(objA, objB) {
    if (objA === objB) {
      return true;
    }
    var key;
    // Test for A's keys different from B.
    for (key in objA) {
      if (objA.hasOwnProperty(key) &&
          (!objB.hasOwnProperty(key) || objA[key] !== objB[key])) {
        return false;
      }
    }
    // Test for B's keys missing from A.
    for (key in objB) {
      if (objB.hasOwnProperty(key) && !objA.hasOwnProperty(key)) {
        return false;
      }
    }
    return true;
  }
docs: Performs equality by iterating through keys on an object and returning
  false when any key has values which are not strictly equal between
  objA and objB. Returns true when the values of all keys are strictly equal.
  
  @return {boolean}