Learning Redux

.toBe or .not.toBe

The toBe matcher uses === to test for exact equality. This works well for primitive values such as numbers or strings.

If you want to check the value/contents of objects, you need to use toEqual instead, because two objects are never the exact same (even if they have the same contents). For example:

test('object example', () => {  const data = { hello: 'world' }  data['hi'] = 'world'  expect(data).toEqual({ hello: 'world', hi: 'world' })})

Matchers should explain as closely as possible what you want your code to be doing. For example, after updating the username to dan, expect(username).toBe('dan').

It is also possible to negate matchers by adding a not. prefix; for example, expect(1 + 1).not.toBe(0).