No it’s not.
> Your code doesn’t begin executing until all of the modules are loaded.
This is inaccurate, or at least misleading.
This, or some aspect of it, is both possible and relatively common:
import foo from 'foo';
await foo.bar();
await Promise.all([
import('other'),
import('stuff'),
]);
// Admittedly this is less common but also valid!
import yet from 'more-stuff';
In terms of rarity, dynamic import calls are already quite common for “lazy”/“suspense” or their equivalents in quite a lot of real world code, and likely to become moreso with React Server Components and other similar solutions deferring to server rendering.
Yes, an import statement is [semantically] blocking. But even so it’s important to know that it’s performing async I/O.
> import foo from 'foo';
> await foo.bar();
import baz from 'baz';
baz.foo();
> await Promise.all([
> import('other'),
> import('stuff'),
> ]);
> import yet from 'more-stuff';
// main.js
console.log('a')
await new Promise(res => setTimeout(res, 1000))
console.log('b')
import { foo } from "./foo.js";
// foo.js
export function foo() {
}
console.log('c')
c
a
[one second pause]
b
No, it really isn't. From the POV of the application code it's irrelevant. This is trivially proven by the existence of module bundlers which convert non-dynamic `import` statements into one big file that doesn't do anything asynchronous to initialize.
(edit: fighting with formatting)
You cannot do that. Top-level await is forbidden because CJS require is explicitly synchronous.
> Works just fine, no `await` necessary.
I typed all of that on a phone so I erred on the side of brevity, but suppose either the Promise.all or the awaited imports depended on some result from importing foo.
> I assume this is included to imply that loading `yet` is blocked by the `await Promise.all` above it to show that import statements can run after module resolution. If this was your intent you are mistaken, that import statement is still resolved before execution begins.
I was trying to show that import statements are blocked by prior awaits. I’m not sure what you’re trying to show, but you’d need to log output after the import from foo.js to see how the asynchrony works for that import.
> No, it really isn't. From the POV of the application code it's irrelevant. This is trivially proven by the existence of module bundlers which convert non-dynamic `import` statements into one big file that doesn't do anything asynchronous to initialize.
Compare that to a non-bundled but otherwise similarly optimized app and look at the waterfall.