🚀 Feature Proposal

I'd really like the ability to extend the toEqual matcher. In my case, I would like to call .equals on each of my objects (if it exists), and otherwise resort to the default functionality. I saw this issue (#7351), but it kinda looked like it just stalled...

Motivation

I may have mentioned some of this above, but I want the ability to add extra functionality to the toEqual matcher, without rewriting the entire thing.

Example

// Test setup somewhere (very rough on implementation)
expect.equalityTester((objectA, objectB) => {
  // Do custom .equals checking, otherwise resort to default functionality
})

// In a test
it('correctly checks equality', () => {
  const measurement1 = new Measurement(1, 'ft')
  const measurement2 = new Measurement(12, 'in')

  expect(measurement1).toEqual(measurement2) // Should pass, currently doesn't
})

Pitch

This allows users to extend equality checks as necessary, without large changes