const delay = require('delay');

delay(200)
    .then(() => {
        // executed after 200 milliseconds
    });

somePromise()
    .then(delay(100))
    .then(result => {
        // executed 100 milliseconds after somePromise resolves
        // the result from somePromise is passed through
    });

// and with Babel and async functions
async () => {
    bar();

    await delay(100);

    // executed 100 milliseconds later
    baz();
}();

// there's also delay.reject() that takes the value, and rejects it `ms` later
Promise.resolve('foo')
    .then(delay.reject(100))
    .then(x => blah()) // never executed
    .catch(err => {
        // executed 100 milliseconds later
        // err === 'foo'
    });

// you can also specify the rejection value
Promise.resolve('foo')
    .then(delay.reject(100, 'bar'))
    .then(x => blah()) // never executed
    .catch(err => {
        // executed 100 milliseconds later
        // err === 'bar'
    });