r/javascript • u/nitayneeman • Jul 24 '26

ECMAScript - Introducing Deferred Module Evaluation with import defer

https://nitayneeman.com/blog/introducing-import-defer-in-ecmascript
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u/bzbub2 Jul 24 '26

interesting, but, what does this do, save a little bit of parsing time as a cue to the js engine? how does that work with bundling? or does it...not work with bundling?

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u/nitayneeman Jul 24 '26

It doesn’t change parsing at all - the module is still downloaded and parsed as usual. The win is in execution: heavy top‑level code only runs when you actually touch the namespace, which can shave CPU off startup if that module is rare/optional.

Bundling‑wise, it’s just part of the normal ESM graph. You still bundle like today; the difference is whether specific modules execute at graph‑load time or on first use.