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[Shallow] Implement setState for Hooks and remount on type change (#1…
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…5120)

* Throw away old shallow renderer state on type change

This worked in function components but was broken for classes. It incorrectly retained the old instance even if the type was different.

* Remove _previousComponentIdentity

We only needed this because we didn't correctly reset based on type. Now we do so this can go away.

* Use _reset when unmounting

* Use arbitrary componentIdentity

There was no particular reason it was set to element.type. We just wanted to check if something is a render phase update.

* Support Hook state updates in shallow renderer
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@gaearon
gaearon authored Mar 15, 2019
1 parent 88853f1 commit 781200e
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Showing 3 changed files with 274 additions and 69 deletions.
135 changes: 66 additions & 69 deletions src/ReactShallowRenderer.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@ type Update<A> = {
};

type UpdateQueue<A> = {
last: Update<A> | null,
first: Update<A> | null,
dispatch: any,
};

Expand Down Expand Up @@ -178,6 +178,10 @@ class ReactShallowRenderer {
};

constructor() {
this._reset();
}

_reset() {
this._context = null;
this._element = null;
this._instance = null;
Expand All @@ -192,9 +196,7 @@ class ReactShallowRenderer {
this._isReRender = false;
this._didScheduleRenderPhaseUpdate = false;
this._renderPhaseUpdates = null;
this._currentlyRenderingComponent = null;
this._numberOfReRenders = 0;
this._previousComponentIdentity = null;
}

_context: null | Object;
Expand All @@ -208,16 +210,14 @@ class ReactShallowRenderer {
_dispatcher: DispatcherType;
_workInProgressHook: null | Hook;
_firstWorkInProgressHook: null | Hook;
_currentlyRenderingComponent: null | Object;
_previousComponentIdentity: null | Object;
_renderPhaseUpdates: Map<UpdateQueue<any>, Update<any>> | null;
_isReRender: boolean;
_didScheduleRenderPhaseUpdate: boolean;
_numberOfReRenders: number;

_validateCurrentlyRenderingComponent() {
invariant(
this._currentlyRenderingComponent !== null,
this._rendering && !this._instance,
'Hooks can only be called inside the body of a function component. ' +
'(https://fb.me/react-invalid-hook-call)',
);
Expand All @@ -232,33 +232,44 @@ class ReactShallowRenderer {
this._validateCurrentlyRenderingComponent();
this._createWorkInProgressHook();
const workInProgressHook: Hook = (this._workInProgressHook: any);

if (this._isReRender) {
// This is a re-render. Apply the new render phase updates to the previous
// current hook.
// This is a re-render.
const queue: UpdateQueue<A> = (workInProgressHook.queue: any);
const dispatch: Dispatch<A> = (queue.dispatch: any);
if (this._renderPhaseUpdates !== null) {
// Render phase updates are stored in a map of queue -> linked list
const firstRenderPhaseUpdate = this._renderPhaseUpdates.get(queue);
if (firstRenderPhaseUpdate !== undefined) {
(this._renderPhaseUpdates: any).delete(queue);
let newState = workInProgressHook.memoizedState;
let update = firstRenderPhaseUpdate;
do {
// Process this render phase update. We don't have to check the
// priority because it will always be the same as the current
// render's.
const action = update.action;
newState = reducer(newState, action);
update = update.next;
} while (update !== null);

workInProgressHook.memoizedState = newState;

return [newState, dispatch];
if (this._numberOfReRenders > 0) {
// Apply the new render phase updates to the previous current hook.
if (this._renderPhaseUpdates !== null) {
// Render phase updates are stored in a map of queue -> linked list
const firstRenderPhaseUpdate = this._renderPhaseUpdates.get(queue);
if (firstRenderPhaseUpdate !== undefined) {
(this._renderPhaseUpdates: any).delete(queue);
let newState = workInProgressHook.memoizedState;
let update = firstRenderPhaseUpdate;
do {
const action = update.action;
newState = reducer(newState, action);
update = update.next;
} while (update !== null);
workInProgressHook.memoizedState = newState;
return [newState, dispatch];
}
}
return [workInProgressHook.memoizedState, dispatch];
}
return [workInProgressHook.memoizedState, dispatch];
// Process updates outside of render
let newState = workInProgressHook.memoizedState;
let update = queue.first;
if (update !== null) {
do {
const action = update.action;
newState = reducer(newState, action);
update = update.next;
} while (update !== null);
queue.first = null;
workInProgressHook.memoizedState = newState;
}
return [newState, dispatch];
} else {
let initialState;
if (reducer === basicStateReducer) {
Expand All @@ -273,16 +284,12 @@ class ReactShallowRenderer {
}
workInProgressHook.memoizedState = initialState;
const queue: UpdateQueue<A> = (workInProgressHook.queue = {
last: null,
first: null,
dispatch: null,
});
const dispatch: Dispatch<
A,
> = (queue.dispatch = (this._dispatchAction.bind(
this,
(this._currentlyRenderingComponent: any),
queue,
): any));
> = (queue.dispatch = (this._dispatchAction.bind(this, queue): any));
return [workInProgressHook.memoizedState, dispatch];
}
};
Expand Down Expand Up @@ -373,18 +380,14 @@ class ReactShallowRenderer {
};
}

_dispatchAction<A>(
componentIdentity: Object,
queue: UpdateQueue<A>,
action: A,
) {
_dispatchAction<A>(queue: UpdateQueue<A>, action: A) {
invariant(
this._numberOfReRenders < RE_RENDER_LIMIT,
'Too many re-renders. React limits the number of renders to prevent ' +
'an infinite loop.',
);

if (componentIdentity === this._currentlyRenderingComponent) {
if (this._rendering) {
// This is a render phase update. Stash it in a lazily-created map of
// queue -> linked list of updates. After this render pass, we'll restart
// and apply the stashed updates on top of the work-in-progress hook.
Expand All @@ -409,9 +412,24 @@ class ReactShallowRenderer {
lastRenderPhaseUpdate.next = update;
}
} else {
// This means an update has happened after the function component has
// returned. On the server this is a no-op. In React Fiber, the update
// would be scheduled for a future render.
const update: Update<A> = {
action,
next: null,
};

// Append the update to the end of the list.
let last = queue.first;
if (last === null) {
queue.first = update;
} else {
while (last.next !== null) {
last = last.next;
}
last.next = update;
}

// Re-render now.
this.render(this._element, this._context);
}
}

Expand Down Expand Up @@ -441,17 +459,6 @@ class ReactShallowRenderer {
return this._workInProgressHook;
}

_prepareToUseHooks(componentIdentity: Object): void {
if (
this._previousComponentIdentity !== null &&
this._previousComponentIdentity !== componentIdentity
) {
this._firstWorkInProgressHook = null;
}
this._currentlyRenderingComponent = componentIdentity;
this._previousComponentIdentity = componentIdentity;
}

_finishHooks(element: ReactElement, context: null | Object) {
if (this._didScheduleRenderPhaseUpdate) {
// Updates were scheduled during the render phase. They are stored in
Expand All @@ -466,7 +473,6 @@ class ReactShallowRenderer {
this._rendering = false;
this.render(element, context);
} else {
this._currentlyRenderingComponent = null;
this._workInProgressHook = null;
this._renderPhaseUpdates = null;
this._numberOfReRenders = 0;
Expand Down Expand Up @@ -514,6 +520,9 @@ class ReactShallowRenderer {
if (this._rendering) {
return;
}
if (this._element != null && this._element.type !== element.type) {
this._reset();
}

const elementType = isMemo(element.type) ? element.type.type : element.type;
const previousElement = this._element;
Expand Down Expand Up @@ -574,11 +583,7 @@ class ReactShallowRenderer {
this._mountClassComponent(elementType, element, this._context);
} else {
let shouldRender = true;
if (
isMemo(element.type) &&
elementType === this._previousComponentIdentity &&
previousElement !== null
) {
if (isMemo(element.type) && previousElement !== null) {
// This is a Memo component that is being re-rendered.
const compare = element.type.compare || shallowEqual;
if (compare(previousElement.props, element.props)) {
Expand All @@ -588,7 +593,6 @@ class ReactShallowRenderer {
if (shouldRender) {
const prevDispatcher = ReactCurrentDispatcher.current;
ReactCurrentDispatcher.current = this._dispatcher;
this._prepareToUseHooks(elementType);
try {
// elementType could still be a ForwardRef if it was
// nested inside Memo.
Expand Down Expand Up @@ -626,14 +630,7 @@ class ReactShallowRenderer {
this._instance.componentWillUnmount();
}
}

this._firstWorkInProgressHook = null;
this._previousComponentIdentity = null;
this._context = null;
this._element = null;
this._newState = null;
this._rendered = null;
this._instance = null;
this._reset();
}

_mountClassComponent(
Expand Down
42 changes: 42 additions & 0 deletions src/__tests__/ReactShallowRenderer-test.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1565,4 +1565,46 @@ describe('ReactShallowRenderer', () => {
'forwardRef requires a render function but was given object.',
);
});

it('should let you change type', () => {
function Foo({prop}) {
return <div>Foo {prop}</div>;
}
function Bar({prop}) {
return <div>Bar {prop}</div>;
}

const shallowRenderer = createRenderer();
shallowRenderer.render(<Foo prop="foo1" />);
expect(shallowRenderer.getRenderOutput()).toEqual(<div>Foo {'foo1'}</div>);
shallowRenderer.render(<Foo prop="foo2" />);
expect(shallowRenderer.getRenderOutput()).toEqual(<div>Foo {'foo2'}</div>);
shallowRenderer.render(<Bar prop="bar1" />);
expect(shallowRenderer.getRenderOutput()).toEqual(<div>Bar {'bar1'}</div>);
shallowRenderer.render(<Bar prop="bar2" />);
expect(shallowRenderer.getRenderOutput()).toEqual(<div>Bar {'bar2'}</div>);
});

it('should let you change class type', () => {
class Foo extends React.Component {
render() {
return <div>Foo {this.props.prop}</div>;
}
}
class Bar extends React.Component {
render() {
return <div>Bar {this.props.prop}</div>;
}
}

const shallowRenderer = createRenderer();
shallowRenderer.render(<Foo prop="foo1" />);
expect(shallowRenderer.getRenderOutput()).toEqual(<div>Foo {'foo1'}</div>);
shallowRenderer.render(<Foo prop="foo2" />);
expect(shallowRenderer.getRenderOutput()).toEqual(<div>Foo {'foo2'}</div>);
shallowRenderer.render(<Bar prop="bar1" />);
expect(shallowRenderer.getRenderOutput()).toEqual(<div>Bar {'bar1'}</div>);
shallowRenderer.render(<Bar prop="bar2" />);
expect(shallowRenderer.getRenderOutput()).toEqual(<div>Bar {'bar2'}</div>);
});
});
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