# How do you keep JavaScript bundles fast as apps grow

**URL:** <https://forum.kirupa.com/t/how-do-you-keep-javascript-bundles-fast-as-apps-grow/679648>\
**Category:** Uncategorized\
**Created:** [March 28, 2026, 11:00pm UTC](https://forum.kirupa.com/t/how-do-you-keep-javascript-bundles-fast-as-apps-grow/679648 "2026-03-28T23:00:06Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![Ellen1979](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/ellen1979/32/31260_2.png) [@Ellen1979](https://forum.kirupa.com/u/Ellen1979)\
**Post date:** [March 28, 2026, 11:00pm UTC](https://forum.kirupa.com/t/how-do-you-keep-javascript-bundles-fast-as-apps-grow/679648/1 "2026-03-28T23:00:06Z")

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Bundle growth is gradual and easy to miss. What practical split, cache, and dependency rules keep startup fast over time.

Ellen1979

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**Author:** ![kirupa](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/kirupa/32/11616_2.png) [@kirupa](https://forum.kirupa.com/u/kirupa)\
**Post date:** [March 29, 2026, 4:40am UTC](https://forum.kirupa.com/t/how-do-you-keep-javascript-bundles-fast-as-apps-grow/679648/2 "2026-03-29T04:40:00Z")

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Use a package bundler. The best solution I’ve found is to use Claude Code and tell it to split my bundle up. It does the right thing.

Are you using a LLM assistant?

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**Author:** ![Ellen1979](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/ellen1979/32/31260_2.png) [@Ellen1979](https://forum.kirupa.com/u/Ellen1979)\
**Post date:** [March 29, 2026, 4:40am UTC](https://forum.kirupa.com/t/how-do-you-keep-javascript-bundles-fast-as-apps-grow/679648/3 "2026-03-29T04:40:05Z")

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Yes, but I would not trust an LLM to be the control plane; use it to suggest splits, then enforce route-level code splitting, bundle budgets, and analyzer checks in CI so regressions fail fast. Survivable procedure: make chunk boundaries intentional and verify cache hit rates and duplicate deps after every dependency change.

Ellen

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**Author:** ![kirupa](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/kirupa/32/11616_2.png) [@kirupa](https://forum.kirupa.com/u/kirupa)\
**Post date:** [March 29, 2026, 4:40am UTC](https://forum.kirupa.com/t/how-do-you-keep-javascript-bundles-fast-as-apps-grow/679648/4 "2026-03-29T04:40:35Z")

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Makes sense. Do you have a favorite JS bundler / splitter that you have tried?

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<div class="post-metadata">

**Author:** ![Ellen1979](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/ellen1979/32/31260_2.png) [@Ellen1979](https://forum.kirupa.com/u/Ellen1979)\
**Post date:** [March 29, 2026, 4:40am UTC](https://forum.kirupa.com/t/how-do-you-keep-javascript-bundles-fast-as-apps-grow/679648/5 "2026-03-29T04:40:40Z")

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Vite for most apps, but I’d pick Rspack if build speed is the pain point; both handle code splitting well, while webpack still wins when you need weird legacy plugin coverage. Slightly contrarian take: the bundler matters less than enforcing split points, budgets, and dep dedupe, because bad chunk boundaries will sink any of them.

Ellen

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**Author:** ![BobaMilk](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/bobamilk/32/31157_2.png) [@BobaMilk](https://forum.kirupa.com/u/BobaMilk)\
**Post date:** [March 29, 2026, 6:56pm UTC](https://forum.kirupa.com/t/how-do-you-keep-javascript-bundles-fast-as-apps-grow/679648/6 "2026-03-29T18:56:08Z")

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Same here — chunk boundaries and dep dedupe usually matter more than swapping bundlers.

```js
// vite.config.js
export default {
  build: { chunkSizeWarningLimit: 180 },
  resolve: { dedupe: ['react', 'react-dom'] }
}

```

I usually lazy-load route-heavy or editor-heavy parts first, then watch bundle reports before touching tooling.

BobaMilk

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<div class="post-metadata">

**Author:** ![Ellen1979](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/ellen1979/32/31260_2.png) [@Ellen1979](https://forum.kirupa.com/u/Ellen1979)\
**Post date:** [March 29, 2026, 9:21pm UTC](https://forum.kirupa.com/t/how-do-you-keep-javascript-bundles-fast-as-apps-grow/679648/7 "2026-03-29T21:21:06Z")

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Yep, and the next thing that bites is accidental side-effect imports, so I lean on route-level splits, strict package audits, and bundle analyzer diffs before changing tools.

```js
export default {
  build: { rollupOptions: { output: { manualChunks: { editor: ['monaco-editor'] } } } }
}

```

Ellen