# Context
Edge SSR'd routes cold boot performances are proportional to the
executed code size.
In order to improve it, we are trying to optimize for the bundle size of
a packed Edge SSR route.
This PR adds ESM compilation targets for all Next.js dist packages and
use them to bundle Edge SSR'd route.
This allows us to leverage the better tree shaking/DCE for ESM modules
in webpack in order to decrease the overall bundle size.
This PR also enables minifying Edge SSR routes. Since we don't control
which minifier might be used later (if any), it's best if we provide an
already optimised bundle.
<img width="903" alt="image"
src="https://user-images.githubusercontent.com/11064311/190005211-b7cb2c58-a56a-44b0-8ee4-fd3f603e41bd.png">
This is a 10ms cold boot win per my benchmarking script, which I'll put
in a subsequent PR.
Not done yet:
- ~~swap exported requires in `next/link` (and others) etc to point them
to the esm modules version~~
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## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [x] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The examples guidelines are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
Co-authored-by: JJ Kasper <jj@jjsweb.site>
Co-authored-by: Shu Ding <g@shud.in>
11deaaa82b
