This babel transform is a fork of the @babel/plugin-transform-react-jsx transform and is for experimentation purposes only. We don't plan to own this code in the future, and we will upstream this to Babel at some point once we've proven out the concept.
As per the RFC to simplify element creation, we want to change the JSX transform from targeting React.createElement(type, props, children) to React.jsx(type, props, key). This modifies the existing @babel/plugin-transform-react-jsx (and helper) babel plugin to support React.jsx and React.jsxDEV.
The main differences between React.jsx/React.jsxDEV and React.createElement are:
1.) key is now passed as an explicit argument rather than through props
3.) children are now passed through props rather than as an explicit argument
4.) props must always be an object
5.) __source and and __self are now passed as separate arguments into React.jsxDEV rather than through props
Part of the rationale for this change is that we want to deprecate key spread through props because this is an expensive dynamic comparison operation. We want users instead always explicitly pass key as a prop. However, in the interim, we need a way to distinguish between <div {...props} key={foo} /> and <div key={foo} {...props} />. Therefore, until we completely deprecate key spreading, we will use React.createElement to transform <div {...props} key="Hi" /> and React.jsx to transform everything else.
* Revert "Revert "[Scheduler] Profiling features (#16145)" (#16392)"
This reverts commit 4ba1412305.
* Fix copy paste mistake
* Remove init path dependency on ArrayBuffer
* Add a regression test for cancelling multiple tasks
* Prevent deopt from adding isQueued later
* Remove pop() calls that were added for profiling
* Verify that Suspend/Unsuspend events match up in tests
This currently breaks tests.
* Treat Suspend and Resume as exiting and entering work loop
Their definitions used to be more fuzzy. For example, Suspend didn't always fire on exit, and sometimes fired when we did _not_ exit (such as at task enqueue).
I chatted to Boone, and he's saying treating Suspend and Resume as strictly exiting and entering the loop is fine for their use case.
* Revert "Prevent deopt from adding isQueued later"
This reverts commit 9c30b0b695.
Unnecessary because GCC
* Start counter with 1
* Group exports into unstable_Profiling namespace
* No catch in PROD codepath
* No label TODO
* No null checks
* Refactor a bit to use less property access
* Add test for invoking an event before mount
* Add Hydration effect tag
This is equivalent to a "Placement" effect in that it's a new insertion
to the tree but it doesn't need an actual mutation.
It is only used to determine if a subtree has actually mounted yet.
* Use the Hydration flag for Roots
Previous roots had a Placement flag on them as a hack for this case but
since we have a special flag for it now, we can just use that.
* Add Flare test
The semantics of 'button' on events differs between PointerEvent and
MouseEvent, whereas they are the same for 'buttons'. Furthermore, 'buttons'
allows developers to determine when multiple buttons are pressed as the same
time.
https://w3c.github.io/pointerevents/#the-button-property
Brian Vaughn