This separates the reconciliation step of children into a separate module.
This is the first step towards prerendering.
The stateful instances are reconciled and put into a "rendered children"
set. Updates creates a new of these sets. These two sets are then diffed
to create insert/move/remove operations on the set.
The next step is to move the ReactChildReconciler step to before the
native DOM component. That way it's possible to rely on child
reconciliation without relying on diffing.
Summary:
After #2570, `mountDepth` is only used to enforce that `setProps` and `replaceProps` is only invoked on the top-level component. This replaces `mountDepth` with a simpler `isTopLevel` boolean set by `ReactMount` which reduces the surface area of the internal API and removes the need to thread `mountDepth` throughout React core.
Reviewers: @sebmarkbage @zpao
Test Plan:
Ran unit tests successfully:
```
npm run jest
```
Currently, `ReactUpdates` updates dirty components in increasing order of mount depth. However, mount depth is only relative to the component passed into `React.render`. This breaks down for components that invoke `React.render` as an implementation detail because the child components will be updated before the parent component.
This fixes the problem by using the order in which components are mounted (instead of their depth). The mount order transcends component trees (rooted at `React.render` calls).
Reviewers: @sebmarkbage @zpao
Test Plan:
Ran unit tests successfully:
```
npm run jest
```
Summary:
Changes the way we instrument methods for `ReactPerf` so that developer tools can assign implicit method names to measured functions.
Reviewers: @zpao @sebmarkbage
Update to the animation documentation for ReactTransitionGroup to clear the air on where one can use it.
If someone tries to use it off of React.addons.ReactTransitionGroup, which is undefined, instead of its real location, React.addons.TransitionGroup, they get a vague error about being unable to set defaultProps of undefined in the React createElement body.
Summary:
Currently, `ReactClass` mutates values returned by `getDefaultProps`, `getInitialState`, and `getChildContext`. This is bad because the objects may, for example, be cached and re-used across instances of a React component.
This changes `ReactClass` to instead create a new object. In return for allocating a new object, I've replaced `mapObject` with a `for ... in` so that we are no longer allocating an unused object.
Fair trade, IMO.
Test Plan:
Ran unit tests successfully:
```
npm run jest
```
Conflicts:
src/core/ReactCompositeComponent.js
Conflicts:
src/class/ReactClass.js
The word "Friends" does establish a relationship however it does not fit in the vernacular of react.
This change makes the phrase more explicit and more familiar.
We currently have three DOM specific hooks that get injected. I move those
out to ReactComponentEnvironment. The idea is to eventually remove this
injection as the reconciler gets refactored.
There is also a BackendIDOperation which is specific to the DOM component
itself so I move this injection to be more specific to the DOMComponent.
E.g. it makes sense for it to be injectable for cross-worker DOM operations
but it doesn't make sense for ART components.
This is part of moving more logic out of the base classes.
setProps, replaceProps etc. are not accessible from anything other than
ReactClass so we can safely move it to ReactCompositeComponent.
mountComponentIntoNode is tightly coupled to ReactMount. It's part of the
outer abstraction, the mount point, not the individual component.
The _owner field is unnecessary since it's reachable from _currentElement.
The _lifeCycle field is unnecessary because an internal component should
not even need to exist at all if it's unmounted. It should be dereferenced
internally, and never exposed externally.
The only case where it's important is for batching updates where we
currently avoid calling performUpdateIfNecessary if it's mounted. However,
this function is already only executed "if necessary" so we just make sure
that it's not necessary after unmount by resetting all the pending fields.
