Posted about 4 years ago. Visible to the public.

Jasmine: Testing complex types for equality

Jasmine comes with two matchers that test for equality. The first is toBe:


toBe passes when first === second. Unfortunately this is useless for non-primitive values because Javascript is a horrible language.

However, Jasmine comes with another matcher toEqual:


This matcher behaves as a human would expect for types like the following:

  • Arrays
  • Objects
  • Nested array/object constructs
  • Regular expressions
  • Date objects
  • NaN
  • Exceptions

Custom equality matchers

You can also teach toEqual additional notions of equality. E.g. the following code will teach toEqual to test two jQuery collections for equality:

beforeEach -> jasmine.addCustomEqualityTester (first, second) -> if first instanceof jQuery && second instanceof jQuery

Using Jasmine's equality logic in your own matchers

You can use Jasmine's built-in equality logic (plus the logic added by custom equality matchers) like this:

beforeEach -> jasmine.addMatchers toEqual123Array: (util, customEqualityTesters) -> compare: (actual) pass: util.equals(actual, [1, 2, 3], customEqualityTesters)

Note how the compare method is passed two arguments util and customEqualityTesters, which are both needed to access Jasmine's equality logic.

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Owner of this card:

Henning Koch
Last edit:
over 3 years ago
by Henning Koch
jasmine, objects
About this deck:
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Posted by Henning Koch to makandra dev
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