This adds the following Node.js core polyfills only when the import is used:
- `path`
- `stream`
- `vm`
- `crypto`
- `buffer`
Fixes#15948
We'll have a separate issue about adding warnings for the usage of these modules in the browser, some polyfills like crypto are quite heavy and generally not needed for most applications (included accidentally through node_modules).
These changes aim to resolve most of the concerns raised in #15756. It adds missing polyfills for legacy browsers up until ES2019:
- Number.{parseFloat,parseInt}
- ~Math.{acosh,asinh,atanh,cbrt,clz32,cosh,expm1,fround,hypot,imul,log10p,log1p,log2,sign,sinh,tanh,trunc}~ _[Removed as these are [not widely used](https://github.com/vercel/next.js/pull/15772#discussion_r463957931)]_
- While these may seem to weigh a lot, they barely add 1 kB to the resulting bundle:
<img width="492" alt="gzip: 32 kB vs. 30.9 kB, Brotli: 28.8 kB vs. 27.8 kB" src="https://user-images.githubusercontent.com/14854048/89100961-1376e600-d3fc-11ea-90fd-3e6632b70220.png">
- ~Object.fromEntries~ _[Removed as [it's rarely used in user code](https://github.com/vercel/next.js/pull/15772#discussion_r463984612)]_
Also, the following features are now supported with build-time transforms:
- ~`globalThis` (gets transformed into `window` in browser environments)~ _[Removed as it [could break existing applications](https://github.com/vercel/next.js/pull/15772#discussion_r463956269)]_
- `export * as ns from 'module'`
The suggested TypeScript library version has been set to ES2018, so the features below become unavailable in type-checked files (they're not evenly supported by module-compatible browsers, either):
- Object.fromEntries
- String.prototype.matchAll
- String.prototype.replaceAll
- Promise.any + AggregateError
- WeakRef
As for the `import.meta` support, [webpack v5 seems to fix that](https://github.com/webpack/webpack/pull/11075), so it should eventually become an issue of the past.
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Fixes#15756
- Use latest terser version (still 1 warning in the stable version which is an open PR)
- Add emitOnErrors instead of noEmitOnErrors
- Added trace-deprecations for Next.js core development
