Mocha, Chai: Assert that Object is included in an Array of Objects

Question

Chai has a nice way to assert if an Array includes a certain element

expect([1,2,3]).to.include(2);

What I would like is something similar, given an Array of Objects:

expect([{a:1},{b:2}]).to.include({b:2});

Is this possible?

Did you try it? The documentation seems to imply that it would work. http://chaijs.com/api/bdd/#include — Schleis, Jul 09 '13 at 21:34
Yeah I tried -- those examples only show how to test if a certain key exists, not the actual value (or entire object for that matter) — mck, Jul 09 '13 at 21:45

random-forest-cat · Answer 1 · 2017-05-02T16:10:35.547

37

Here is an alternative and non order dependent approach for collections:

array

expect([1, 2, 3]).to.include.members([3, 2, 1])

You can also use this with a deep flag for comparison of objects:

expect([{ id: 1 }]).to.deep.include.members([{ id: 1 }]);

expect({foo: 'bar', width: 190, height: 90}).to.include({ height: 90, width: 190 })

edited May 02 '17 at 16:10

answered Oct 25 '16 at 18:59

random-forest-cat

score 26 · Accepted Answer · answered Jul 10 '13 at 06:47

26

Take a look at the Chai Things plugin, that does what you want:

[{a:1},{b:2}].should.include.something.that.deep.equals({b:2})

answered Jul 10 '13 at 06:47

Andreas Köberle

and if you had check [{a:1},{a: 2}].contains(['a']) how would you do that – PirateApp Dec 18 '17 at 12:12
1

@PirateApp, I think it may be like this: `[{ a: 'cat' }, { a: 'dog' }].should.all.have.property('a')` https://github.com/chaijs/chai-things#all – andreshg112 Aug 02 '18 at 15:43
Note that Chai Things plugin's last commit was in 2016. – Sylvain Lesage May 20 '20 at 14:08

score 26 · Answer 3 · edited Jun 04 '18 at 09:45

26

You can use deep method for the array of objects.

expect([{a:1},{b:2}]).to.deep.include({b:2});   //It will pass

You can find more examples using deep method here: http://chaijs.com/api/bdd/#method_deep

The main point to remember here is about reference types.

edited Jun 04 '18 at 09:45

Aleksey Solovey

answered Nov 13 '17 at 08:16

Jyothi

I should have seen this solution before! This worked for me since chai-things seems not supported in Chai v4 – Rashomon Jun 04 '18 at 08:57
this is a better solution as it doesn't require to use another dependency – Technotronic Apr 23 '20 at 08:25