perf(js): externalize deps and split entry points for tree shaking

[adambrudzynski]

Summary

Externalizes @storyblok/richtext and storyblok-js-client from the @storyblok/js bundle and splits the package into individual entry points — enabling proper tree shaking and code splitting for downstream bundlers.

Problem

@storyblok/js was shipping as a single monolithic bundle (storyblok-js.mjs) with all dependencies inlined. This meant:

• storyblok-js-client and @storyblok/richtext were bundled twice — once inside @storyblok/js and again as standalone packages
• Importing any single export (e.g. storyblokEditable) pulled the entire bundle into the consumer's app
• No tree shaking was possible for downstream bundlers (Next.js, Vite, etc.)

Solution

Mirrors the pattern already established in @storyblok/react, which externalizes react, react-dom, and @storyblok/js itself.

vite.config.ts changes:

• @storyblok/richtext and storyblok-js-client marked as external
• preserveModules: true — each source file gets its own output file
• Multiple named entry points: index, api, bridge, editable

package.json changes:

• exports map updated with sub-path exports for each entry point
• main/module updated from storyblok-js.js → index.js/index.mjs

Before / After

	Before	After
index.mjs	large inlined bundle	2.18 kB
api.mjs	inlined	0.39 kB
bridge.mjs	inlined	0.81 kB
editable.mjs	inlined	0.37 kB

Bundle analysis — Next.js application

Before
Huge bundle of @storyblok/js when using only @storyblok/react and @storyblok/richtext packages

After

Test plan

• pnpm build — clean output with externalized imports verified
• pnpm test:unit — 19/19 passing
• pnpm run test:types — no type errors
• pnpm test:e2e — 4/4 passing
• Tested in real Next.js app via yalc — build succeeds, externals confirmed as import statements in output