`await` Slower Than It Should Be In Chrome
You can easily observe a difference between an await
expression and lack thereof. At the very least, you are asking the engine to look at the microtask queue, possibly doing other work that happened as a result of I/O completing. Given that, this cannot possibly be optimized into nothing.
If you truly wish to spin the CPU for a few milliseconds, don't write await
.
Here's an example. It prints 1 2 3
.
Promise.resolve().then(()=>console.log(2));(async()=>{ console.log(1); await undefined; console.log(3);})();
await undefined
is not a "do-nothing" statement. It's JavaScript's cooperative multitasking.