We were using `Object.create` to setup the prototype chain at the start of the class definition, which lead to #7771.
I was a bit worried about a speed hit, but it seems everyone optimizes the two patterns the same way.
https://jsbench.github.io/#f9fca52407643d96458a35763b201215Fixes#7771.
* #7349
- Add "use strict" directive to transformed class bodies
* Update tests (#7349)
* Add test for program with use strict directive (#7349)
* Update tests (#7349)
* Update source mapping (#7349)
* Add test for parent blockStatement with use strict directive (#7349)
* Update tests (#7349)
* Update tests (#7349)
* Update tests (#7349)
* Add test for constructor-only class (#7349)
* Constructor only classes are strict, too
But constructor only that use non-simple parameters must use a strict function wrapper.
* Fix test
* Wrapper not needed if class is already strict
* Revert change to lerna.json
* centralize plugin options
* Centralize plugins options
- move more options to the top
- move validations that depend on options to the top
* use isLoose option
* Move more validations to the top
* Move ref parameter for rewriteModuleStatementsAndPrepareHeader() to the top
* fix eslint errors
* remove unused parameter
* set default systemGlobal value
* Revert "Move ref parameter for rewriteModuleStatementsAndPrepareHeader() to the top"
This reverts commit b3855302d17fa19d8acb4c8accab3680c8d2710e.
* Revert "Move more validations to the top"
This reverts commit e5861d8a034ff8f553391f55654f753bcf428a5d.
* fix allowMutablePropsOnTags option usage
* improve naming
* change Contructor definition for sake of consistency
* move allowMutablePropsOnTags validation to the top
* add missing !
