Using toInclude and toExclude

The toInclude assertion checks if an array or an object includes some things. Now if it's an array, we can check if it includes a certain item in the array. If it's an object, we can check if it includes certain properties. Let's run through an example of that.

We'll expect that an array with the numbers 2, 3, and 4 inside the it callback has the number 5 inside and we can do that using toInclude:

it('should expect some values', () => {  // expect(12).toNotBe(12);  // expect({name: 'andrew'}).toNotEqual({name: 'Andrew'});  expect([2,3,4]).toInclude(5);});

The toInclude assertion takes the item. In this case, we'll check if the array has 5 inside. Now clearly it doesn't, so this test will fail:

We get the message, ...

Get Learning Node.js Development now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.