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Why is my ES6 module not being tree-shaken properly during the build process?
Asked on Jan 14, 2026
Answer
Tree shaking is a process used to eliminate dead code from your JavaScript bundles. If your ES6 module isn't being tree-shaken properly, it might be due to how the code is structured or how the build tool is configured. Here's a simple example of how to ensure your modules are tree-shakeable:
<!-- BEGIN COPY / PASTE -->
// utils.js
export const usefulFunction = () => {
console.log("This is a useful function");
};
export const unusedFunction = () => {
console.log("This function is not used");
};
// main.js
import { usefulFunction } from './utils.js';
usefulFunction();
<!-- END COPY / PASTE -->Additional Comment:
✅ Answered with JavaScript best practices.- Ensure you are using ES6 "import" and "export" syntax, as tree shaking relies on static analysis of these statements.
- Confirm that your build tool (e.g., Webpack, Rollup) is configured to support tree shaking. For Webpack, ensure the "mode" is set to "production".
- Avoid using dynamic imports or CommonJS syntax, as they can interfere with tree shaking.
- Check if any plugins or configurations in your build process are preventing tree shaking.
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