jsdoc/packages/jsdoc-util/test/specs/lib/bus.js

describe('@jsdoc/util/lib/bus', () => {
  const EventBus = require('../../../lib/bus');
  const EventEmitter = require('events').EventEmitter;

  const ignoreCache = { cache: false };

  it('inherits from EventEmitter', () => {
    expect(new EventBus('foo', ignoreCache) instanceof EventEmitter).toBeTrue();
  });

  it('accepts a string for the ID', () => {
    function makeBus() {
      return new EventBus('foo', ignoreCache);
    }

    expect(makeBus).not.toThrow();
  });

  it('accepts a Symbol for the ID', () => {
    function makeBus() {
      return new EventBus(Symbol('foo'), ignoreCache);
    }

    expect(makeBus).not.toThrow();
  });

  it('throws on bad IDs', () => {
    function crashBus() {
      return new EventBus(true, ignoreCache);
    }

    expect(crashBus).toThrowError();
  });

  it('uses a cache by default', () => {
    let fired = false;
    const id = Symbol('cache-test');
    const bus1 = new EventBus(id);
    const bus2 = new EventBus(id);

    bus1.once('foo', () => {
      fired = true;
    });

    bus2.emit('foo');

    expect(bus1).toBe(bus2);
    expect(fired).toBeTrue();
  });

  it('ignores the cache when asked', () => {
    let fired = false;
    const id = Symbol('cache-test');
    const bus1 = new EventBus(id, ignoreCache);
    const bus2 = new EventBus(id, ignoreCache);

    bus1.once('foo', () => {
      fired = true;
    });

    bus2.emit('foo');

    expect(bus1).not.toBe(bus2);
    expect(fired).toBeFalse();
  });
});