Contrary to what it seems, await does not block. It’s just syntactic sugar over promises. Nothing is blocked; it may look blocking to allow code to be synchronous, but that’s just sugar over promises. For example, this may look synchronous:
const response = await fetch(…);
const json = await response.json();
const foo = JSON.parse(json); // Using json here, even though my request was async!
But it’s not. Once you desugar it, all you get are promises, which are nonblocking:
fetch(…)
.then(response => response.json())
.then(json => {
const foo = JSON.parse(json);
});
It would be absolutely catastrophic if await were blocking. JavaScript runtimes are generally single threaded. That means user interaction and other processes would cease whenever you made a request or some other async operation such as using the filesystem. On a related note, this is, along with dynamic imports, are the main argument against top level await