Most developers would agree that, all other things being equal, a synchronous program is easier to work with than an asynchronous one. The logic for this is pretty clear: one flow of execution is easier for the human mind to simulate than n
concurrent flows.
After doing two small projects in node.js (one of which is here -- ready for the blinding flurry of criticism), there's one question that I can't shake: if asynchronicity is an optimization (that is, a complexity introduced for the sake of performance), why would people, a priori, turn to a framework that imposes it for everything? If asynchronous code is harder to reason about, why would we elect to live in a world where it is the default?
It could be argued pretty well that the browser is a domain that inherently lends itself to an async model, but I'd be very curious to hear a defense of "async-first" thinking for problems that are typically solved on the server-side. When working with node, I've noticed many regions of code where
- synchronicity wouldn't introduce a performance bottleneck, and
- what would otherwise be an easy problem is made very difficult by the fact that everything must be phrased for the event loop.
For an example of this, try writing a function call that requires information from two separate HTTP API responses; I basically need to draw a diagram of what happens with async.waterfall
for a task that, given synchronicity, would've been solved with a trivial three-liner.
Easy things should be easy. Optimizations should be closeted until they're needed. Maybe I'm missing something here, some mechanism in node that allows opt-in synchronicity... dear node.js, is there such a thing? If not, why do you want to make many things harder than they need to be?
Asynchronous scripting takes some time to get used to, but when you get used to it, it's not any harder then reading any other language that has functions / subroutines / jumping to labels.
function cakeReady(cake) {
·· eat(cake);
}
bakeCake(cakeReady);
But if you really want to read from line to line and not jump between functions, you can in-line the function:
bakeCake(function cakeReady(cake) {
·· eat(cake);
});
And some people like to add the word "then" to make it easier to follow (aka "promises")
bakeCake().then(cakeReady);
You can also use the OO-pattern:
var cake = new Cake();
cake.ready = cakeReady;
And some people prefer:
cake.on("ready", cakeReady);