fix(nuxt): ensure component helper methods do not create side-effects

[danielroe]

🔗 Linked issue

resolves nuxt/nuxt#14650

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

Lazy components (defined with defineAsyncComponent) were marked as having a side effect, so were persisting into the routes bundle. We should certainly not be including async component statements within the entry bundle, which also had the effect of marking them as dependencies of the entry rather than the page they correspond to (resulting in over-prefetching - see nuxt/nuxt#14584).

---

Note that I encountered this when debugging what I believe to be an upstream rollup bug that I'm still looking into, which is difficult to reproduce but essentially boils down to two modules which each contain:

defineAsyncComponent(() => __vitePreload(() => import('./Text.3d3cd0e1.js'),true?"__VITE_PRELOAD__":void 0,import.meta.url));
const meta = undefined;

being transformed into:

defineAsyncComponent(() => __vitePreload(() => import('./Text.3d3cd0e1.js'),true?"__VITE_PRELOAD__":void 0,import.meta$1.url));
const meta$1 = undefined;

defineAsyncComponent(() => __vitePreload(() => import('./Text.3d3cd0e1.js'),true?"__VITE_PRELOAD__":void 0,import.meta.url));
const meta = undefined;

(This seems like an over-zealous search + replace on the part of rollup.)

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

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[pi0]

Nice find!!

[simirka]

@danielroe Hey, I am not sure if this is something on my side or after the new changes.
But after upgrading to a new rc.9 I am having this error, on the rc.8 all is working.

Expected "meta" but found "meta$k"
13877|
13878|  defineAsyncComponent(() =>
13879|      __vitePreload(() => import('./Test.0f9d27a0.js'),true?"__VITE_PRELOAD__":void 0,import.meta$k.url)
13881|  const meta$k = {
``

[danielroe]

@simirka can you create a minimal reproduction?

[simirka]

@danielroe Try to build it
https://codesandbox.io/s/suspicious-cherry-pqq6ci?file=/pages/test.vue

Attaching screenshot