我可以分配使用Moment.js的“现在”吗？

Question

I'm using moment.js and I want to write a test that says, "If you do not pass in a date, it returns now() ". The problem is, every time the test runs, now() will be a different result. In other libraries, you can set what now() will return for testing purposes. Does moment.js provide a way to do that? I've been googling and not finding any results that say whether or not you can do this.

Answer 1

Timekeeper ( https://www.npmjs.com/package/timekeeper ) fills this exact need.

It overrides the date constructors (which moment uses under the hood) so it will work for moment as well.

You can do the following:

const timekeeper = require('timekeeper');

const freezeDate = new Date();
timekeeper.freeze(freezeDate);

// in your test
expect(result).to.equal(freezeDate);

Answer 2

You can change the time source (which basically overrides the implementation with a new Date.now ) before each test by doing the following from the official momentjs docs . This returns the number of milliseconds since unix epoch time (1/1/1970).

moment.now = function () {
    return +new Date();
}