Mastering JavaScript Promises

Aborting a promise

We saw how done(); is used earlier, but here it comes in with a total impression.

Using done();, we can conclude our promise and abort our program. I always have a way to chain the promises:

then().then().done();

If the promise is vetted (and did not catch the error before), the done() function forcibly spawns an uncatchable error (for example, setTimeout(function () {throw ex;}, 0)).

On Node.js REPL, run Q.reject("uncaught").done(), then exit with an error.

If the error reached to the done() function, you can think of it just a programming bug (not an exception state).