Why does this QUnit test fail?

Question

I'm trying to learn about unit testing and I found this overview by Ben Alman. On slide 23, he shows how a variable named actual containing an object {a: 1} is not equal to just the object itself. What does that mean? Aren't they the same value? How can the objects be different?

test("deepEqual", 7, function() {
  var actual = {a: 1};

  equal(    actual, {a: 1},   "fails because objects are different");
  deepEqual(actual, {a: 1},   "passes because objects are equivalent");
  deepEqual(actual, {a: "1"}, "fails because '1' !== 1");

  var a = $("body > *");
  var b = $("body").children();

  equal(    a,       b,       "fails because jQuery objects are different");
  deepEqual(a,       b,       "fails because jQuery objects are not equivalent");
  equal(    a.get(), b.get(), "fails because element arrays are different");
  deepEqual(a.get(), b.get(), "passes because element arrays are equivalent");
});

Answer 1

Objects in JS are never the same even if their values appear to be. In mostly comes down to being different instances. Read more on Sameness in JavaScript. There are also much better answers on the real details on StackOverflow.

You can see how deepEqual determines an object's "sameness" here. Another good one to look at is lodash's implementation