Async.js - Is parallel really parallel?

Question

As I have understood so far: Javascript is single threaded. If you defer the execution of some procedure, you just schedule it (queue it) to be run next time the thread is f

Answer 1

Async.Parallel is well documented here: https://github.com/caolan/async#parallel

Async.Parallel is about kicking-off I/O tasks in parallel, not about parallel execution of code. If your tasks do not use any timers or perform any I/O, they will actually be executed in series. Any synchronous setup sections for each task will happen one after the other. JavaScript remains single-threaded.