react-hook-form/src/__tests__/utils/isNullOrUndefined.test.ts

import isNullOrUndefined from '../../utils/isNullOrUndefined';

describe('isNullOrUndefined', () => {
  it('should return true when object is null or undefined', () => {
    expect(isNullOrUndefined(null)).toBeTruthy();
    expect(isNullOrUndefined(undefined)).toBeTruthy();
  });

  it('should return false when object is neither null nor undefined', () => {
    expect(isNullOrUndefined(-1)).toBeFalsy();
    expect(isNullOrUndefined(0)).toBeFalsy();
    expect(isNullOrUndefined(1)).toBeFalsy();
    expect(isNullOrUndefined('')).toBeFalsy();
    expect(isNullOrUndefined({})).toBeFalsy();
    expect(isNullOrUndefined([])).toBeFalsy();
  });
});