function toBeNullish() {
    return {
      compare: function(actual) {
        return {
          pass: null === actual || void 0 === actual
        };
      }
    };
  }
{@link expect} the actual value to be `null` or `undefined`.
@function
@name matchers#toBeNullish
@since 5.6.0
@example
expect(result).toBeNullish():