Add sideEffects: false flag to package.json to allow tree-shaking

[josdejong]

I have a library that amongst others exports a utility function createAjvValidator that uses ajv. Now, not all users of my library use this utility function, but I noticed that the Ajv library is always included when creating a js bundle containing my library, also when the ajv utility function is not used at all. It turns out that tree-shaking is not working.

Can the flag "sideEffects": false be added to the package.json file of ajv? That will enable tree shaking by Vite/Rollup/Webpack out of the box.

See:

• https://webpack.js.org/guides/tree-shaking/#mark-the-file-as-side-effect-free
• Add support for sideEffects hint in resolveId rollup/rollup#2593

[jasoniangreen]

Sure @josdejong, do you want to make a PR for it and I'll run it by @epoberezkin ?

[josdejong]

Definitely! Here you go: #2480

[jasoniangreen]

Merged. Not sure when it will go out, but I'll keep you posted.

[josdejong]

Thanks Jason 👍

[josdejong]

Any news on this @jasoniangreen? A bug fix release would be very welcome 😅