@esutils/deferred/test/deferred-in-mjs.test.js

The deferred library implemented in Typescript

const { Deferred } = require('@esutils/deferred');

describe('Deferred in javascript', () => {
  it('constructor type', () => {
    expect(typeof Deferred).toBe('function');
  });

  it('constructor instance', () => {
    expect(new Deferred()).toBeInstanceOf(Deferred);
  });
});