Vue Academy · Lesson

Tree-Shaking and Auto-Import

Named exports for tree-shaking, unplugin-vue-components integration, resolver config.

Lesson 3 of 413 steps

Tree-Shaking and Auto-Import is a free Vue Academy lesson on CoddyKit. This is lesson 3 of 4. Any 3 lessons of this learning path are free to read in full — after that, CoddyKit PRO unlocks every lesson, plus hands-on practice with a built-in code editor and a 24/7 AI tutor. It is part of the Vue Academy learning path, and your progress syncs across the web and the CoddyKit app. The Vue Academy course includes 4 lessons in total.

What is Tree-Shaking

Tree-shaking is dead-code elimination: a bundler drops exports the consumer never imports. A well-built library lets apps include only the components they use, keeping bundles small.

Named Exports Enable It

Use named exports from your entry so each import is statically analyzable. A single default export holding everything (a barrel object) cannot be tree-shaken.

// GOOD: named exports
export { MyButton } from "./MyButton.vue";
export { MyCard } from "./MyCard.vue";

Avoid a Default Barrel Object

Exporting one object with all components forces bundlers to keep them all, even if the app uses one.

// BAD: defeats tree-shaking
export default { MyButton, MyCard, MyTable };

Consumer Imports What They Need

With named exports, the consumer destructures only used components and the rest is dropped from their build.

import { MyButton } from "my-ui-lib";
// MyCard, MyTable are never bundled

The sideEffects Field

Bundlers assume modules may have side effects and keep them. Setting "sideEffects": false in package.json tells them your modules are pure and safe to prune.

{
  "sideEffects": false
}

Declaring CSS Side Effects

If your package has CSS imports that must not be dropped, list them so only those are preserved.

{
  "sideEffects": ["**/*.css"]
}

Auto-Import for Consumers

To save consumers from manual imports, libraries ship a resolver for unplugin-vue-components, which auto-imports components used in templates.

npm install -D unplugin-vue-components

Providing a Resolver

A resolver is a function that, given a used component name, returns where to import it from. Ship one from your package.

// my-ui-lib/resolver.js
export function MyUiResolver() {
  return {
    type: "component",
    resolve: (name) => {
      if (name.startsWith("My")) {
        return { name, from: "my-ui-lib" };
      }
    }
  };
}

Consumer Config

The consumer registers the plugin with your resolver. Now components used in templates are imported automatically and still tree-shaken.

// consumer vite.config.ts
import Components from "unplugin-vue-components/vite";
import { MyUiResolver } from "my-ui-lib/resolver";

export default defineConfig({
  plugins: [
    vue(),
    Components({ resolvers: [MyUiResolver()] })
  ]
});

Auto-Import Plus Tree-Shaking

Because the resolver turns template usage into real named imports, only used components are bundled - you keep both ergonomics and small bundles.

Avoid Global Registration

A library that auto-registers all components via app.use kills tree-shaking. Prefer named exports and an optional resolver so consumers opt in per component.

Quick Check

What package.json setting tells bundlers your modules are safe to tree-shake?

Answer it in the interactive lesson

Recap

Enable tree-shaking by using named exports (never a default barrel object) and setting "sideEffects": false (or listing CSS). For ergonomics, ship an unplugin-vue-components resolver so consumers auto-import used components while still bundling only what they use - and avoid forcing global registration.

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Frequently Asked Questions

Is the “Tree-Shaking and Auto-Import” lesson free?

Yes — any 3 lessons of the Vue Academy learning path, including “Tree-Shaking and Auto-Import”, are free to read in full here on the web. After that, CoddyKit PRO unlocks every lesson, plus interactive practice with a built-in code editor and a 24/7 AI tutor. The Vue Academy course includes 4 lessons in total.

What will I learn in “Tree-Shaking and Auto-Import”?

Named exports for tree-shaking, unplugin-vue-components integration, resolver config. You practise Vue Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Vue Academy?

No prior experience is required. Vue Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 3 of 4.

How long does the “Tree-Shaking and Auto-Import” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Vue Academy lesson?

Yes. Every Vue Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

Vite Library Mode Configuration
TypeScript Declarations for Component Libraries
Tree-Shaking and Auto-Import
Publishing to npm and Semantic Versioning

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