lodash-es#bind TypeScript Examples

The following examples show how to use lodash-es#bind. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example #1
Source File: negate.spec.ts    From s-libs with MIT License 5 votes vote down vote up 
describe('negate()', () => {
  function isEven(n: number): boolean {
    return n % 2 === 0;
  }

  //
  // stolen from https://github.com/lodash/lodash
  //

  it('should create a function that negates the result of `func`', () => {
    const negated = negate(isEven);

    expect(negated(1)).toBe(true);
    expect(negated(2)).toBe(false);
  });

  it('should create a function that negates the result of `func`', () => {
    const negated = negate(isEven);

    expect(negated(1)).toBe(true);
    expect(negated(2)).toBe(false);
  });

  it('should create a function that accepts multiple arguments', () => {
    const spy = jasmine.createSpy();
    const negated = negate(spy);

    negated();
    expectSingleCallAndReset(spy);

    negated(1);
    expectSingleCallAndReset(spy, 1);

    negated(1, 2);
    expectSingleCallAndReset(spy, 1, 2);

    negated(1, 2, 3);
    expectSingleCallAndReset(spy, 1, 2, 3);

    negated(1, 2, 3, 4);
    expectSingleCallAndReset(spy, 1, 2, 3, 4);
  });

  it('should use `this` binding of function', () => {
    const fn = function (this: any): boolean {
      return this.a;
    };
    const object: any = { a: 1 };

    let negated = negate(bind(fn, object));
    expect(negated()).toBe(false);

    negated = bind(negate(fn), object);
    expect(negated()).toBe(false);

    object.wrapper = negate(fn);
    expect(object.wrapper()).toBe(false);

    const spy = jasmine.createSpy();
    object.spied = negate(spy);
    object.spied();
    expect(spy.calls.mostRecent().object).toBe(object);
  });
});