browserslist VS rollup-plugin-terser

Yeah, supporting iOS 12 in 2025 is odd. I was investigating browser support levels just recently for a library and also settled on iOS 16 as a reasonable level.

For reference, iOS 12.x and below are used 0.33% globally https://browsersl.ist/#q=safari+%3C+13+or+ios+%3C+13. Selecting iOS 16 would still exclude less than 1% globally https://browsersl.ist/#q=safari+%3C+16+or+ios+%3C+16. In both cases the vast majority would be older iOS which is unfortunate because I assume they're on older devices with no upgrade path, but you have to decide on the transpile /polyfill cutoff at some point and browser support has an extremely long tail.

a browser targeted script in lib/ with the original ES Module exports, leveraging a browserslist query for which browser features to transpile support for

This plugin automatically converts modern JavaScript and adds necessary polyfills based on Browserlist-targets using Babel.

For a production build, you are likely using Browserslist, by default Vite targets browsers that support native ES Modules, native ESM dynamic import, and import.meta.

Not these days, where most people are using evergreen browsers and iOS users upgrade very quickly.

Take a look at the defaults for browserslist, for example:

https://browsersl.ist/#q=defaults

It just barely supports Safari 15, on iOS only, and that’s likely to go away imminently because it’s under 1% usage.

browserslist

We compile JS only for modern browsers. The list of default browsers in Next can be overridden in your browserslist.

In the latest versions of Next.js, targeting specific browsers or features is a breeze using the Browserslist configuration in your package.json file. The latest version of Next.js (v13) uses the following configuration by default:

For a more general answer to browser support, check out https://github.com/browserslist/browserslist. That seems to be standard tool to help you with that.

This next one will help us reduce final bundle size by minifying the generated code. It's called rollup-plugin-terser and uses terser under the hood to minify the code.

Generating a bundle that has many dependencies, from our code or third-party packages, will result in a large JavaScript file. To optimize the bundle it is useful to integrate Terser into our build process. What Terser does is it removes comments, shorten variables names, cut whitespaces and minify our code to make it the shortest possible. Again Terser can be integrated with Rollup using a plugin: