Resolve and reject

The Promise.resolve and Promise.reject functions create Promise objects that immediately resolve or reject with the given values.

It's a useful shorthand for writing a full function to initialize a Promise object and immediately call resolve or reject with a particular value.

The benefit of doing this, even for synchronous function that don't depend on asynchronous result, is that you can now use the function in a configurable chain of transformations that can include both synchronous and asynchronous work.