jest-toContainObject.js

expect.extend({
  toContainObject(received, argument) {

    const pass = this.equals(received, 
      expect.arrayContaining([
        expect.objectContaining(argument)
      ])
    )

    if (pass) {
      return {
        message: () => (`expected ${this.utils.printReceived(received)} not to contain object ${this.utils.printExpected(argument)}`),
        pass: true
      }
    } else {
      return {
        message: () => (`expected ${this.utils.printReceived(received)} to contain object ${this.utils.printExpected(argument)}`),
        pass: false
      }
    }
  }
})

const state = [
  { type: 'START', data: 'foo' },
  { type: 'START', data: 'baz' },
  { type: 'END', data: 'foo' },
]

expect(state).toContainObject({ type: 'START' })
expect(state).toContainObject({ type: 'END' })
expect(state).toContainObject({ data: 'foo' })
expect(state).not.toContainObject({ type: 'NONE' })
expect(state).not.toContainObject({ data: 'bar' })