Babel-preset-env includes includes optional chaining and
nullish-coalescing since [7.8.0](https://github.com/babel/babel/releases/tag/v7.8.0).
In this diff I removed these plugins from next preset to prevent
dependency duplication when their newer versions are out.
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.
---
Fixes#15756
Was going through _document and noticed some variable shadowing going on. Added a rule for it to our eslint configuration and went through all warnings with @Timer.
* Allow `@babel/preset-typescript` to be configured
Some usages, e.g. [getting parameter decorators to work properly](https://github.com/WarnerHooh/babel-plugin-parameter-decorator/pull/19), require configuring `@babel/preset-typescript`.
This commit adds that functionality to `next/babel`.
* Add unit test for babel/preset allowing to pass options to @babel/preset-typescript
* Add integration test for onlyRemoveTypeImports
* Update babel dependencies
* Update to compatible typescript version and fix types
* Fix linting and run pre-nccing
* Update size-limit test
* Add additional tests
* Re-Apply delta to be calculated using -262
Co-authored-by: JJ Kasper <jj@jjsweb.site>
* Add transparent JSX optimization.
* fix duplicate React import
* fix React not being imported when only a single Fragment node is present in a source module
* remove babel-plugin-react-require
* Fix JSX optimization for CommonJS source files.
* Remove accidental support for invalid JavaScript
Next.js inadvertently supported users mixing ES Modules and CommonJS due to a Babel bug that was fixed in v7.
This removes the hack in favor of the new Babel `sourceType` feature.
**This will result in broken code for users who relied on this non-standard conforming behavior.**
* Fix comment
* Toggle feature behind modern flag
* Compile for the current version of Node.js by default when producing server builds.
* Update packages/next/build/babel/preset.ts
Co-Authored-By: Joe Haddad <timer150@gmail.com>
* Include server variation in Babel cacheKey
* Run prettier over packages/**/*.js
* Run prettier over packages/**/*.ts
* Run prettier over examples
* Remove tslint
* Run prettier over examples
* Run prettier over all markdown files
* Run prettier over json files
* Make async-to-promises babel plugin experimental
* Move excludes for asyncToPromises behind flag too
* Move other configs behind flag
* Re-add original exclude item
After discussion it was decided instead of rewriting `next/config` and `next/head` imports to `next-server/config` and `next-server/head` we should just allow importing them as `next/config` and `next/head`
Fixes: #6187