Reduce package size by code splitting

[williazz]

Reduce package size by code splitting

[broofa]

// bad
// the entire package is imported
import { v4 } from 'uuid'

The above is the correct syntax, and does in fact allow modern bundlers to "tree shake" out unused code. (See our examples directory for examples of how this works with rollup and webpack.)

If this isn't working for you - i.e. if your bundles contain code for non-v4 versions - please provide a link to a functional example or repository demonstrating the problem and we can take a look. If there's it turns out to be a valid bug we can reopen this issue.

// good
// only imports v4 and necessary dependencies
import v4 from 'uuid/v4'

This is syntax won't work by design. We dropped support for deep imports a few major-versions back (v7... or maybe v8?)

[williazz]

If this isn't working for you - i.e. if your bundles contain code for non-v4 versions - please provide a link to a functional example or repository demonstrating the problem and we can take a look. If there's it turns out to be a valid bug we can reopen this issue.

Sure this my team's repo https://github.com/aws-observability/aws-rum-web

As shown below via webpack-bundle-analyzer, we are including other modules such as md5, v1, v3 etc. despite our prod config https://github.com/aws-observability/aws-rum-web/blob/main/webpack/webpack.prod.js

How should this be done instead? Hopefully this is just a config error on our end

[williazz]

I've also reviewed https://webpack.js.org/guides/tree-shaking/#root and can't find any issues. We are using the production build, the default minimizer from TerserPlugin, and have marked zero side effects.

[broofa]

'Looks like the problem is that you're transpiling to commonjs, which bundlers aren't able to tree shake. While this project does provide commonjs builds, we don't provide the ability to deep import specific versions the way you're suggesting.

While I acknowledge that's a flaw in the existing API for CJS use cases, it's not something I'm interested in addressing at this time.

How should this be done instead?

Consider bundling for ESM. Failing that, I'd suggest switching from uuid to [crypto.randomUUID()](https://developer.mozilla.org/en-US/docs/Web/API/Crypto/randomUUID), which is broadly supported now.

[williazz]

Thank you so much for the two strong callouts

1. Compiling to commmon js is breaking our tree shaking
2. Backup strategy to use native crypto package for uuids