Type coersion bug and ID breaking assumption.
Names need to be wrapped in something unique since otherwise two unique siblings
can end up having IDs that are subsets of eachother.
Currently we're mutating _key. Mutation here is fine, but it needs to
be idempotent - which it's not. This is causing some issues.
Instead I reassign the _key every time it passes through a flattening.
This means that it's unique and stable for a single pass through a composite
component. When it's repassed another level, it loses it previous
identity and is rekeyed by it's new location.
For auto-generated keys by index, this actually means it has the same
semantics as before flattening.
For explicit keys, it has the effect that keys need to be unique at
every level. Regardless of how the key got there. Every component needs to ensure
that it doesn't combine keys from two different sources that may collide. This
is also inline with the old semantics but less intuitive in the new model.
flattenChildren was only using key when child.mountInContainerNode
exists, which is defined on ReactCompositeComponent, and not
ReactNativeComponent.
This uses the isValidComponent() fn to see if we should use this key.
This expects static children as additional arguments to the constructor
and flattens any array arguments one level deep.
Component(props, child1, child2, arrayOfChildren, child3) ->
.props.children = [child1, child2, ...arrayOfChildren, child3]
This can avoid an additional heap allocation for the unflat array.
It allows you to pass nested arrays and objects like you used to. Those
aren't immediately flattened. That makes this a fairly safe change.
Passing a dynamic array without key properties will yield a warning
(once). Might consider throwing later.
Once we change the transpiler to use the new syntax, you'll end up with
a single flat array in normal usage.
This doesn't actually update the JSX transform.
CommitSyncScriptandPaul O’Shannessy
Ben Newman