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merged 2 commits into from
Nov 15, 2023
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refactor(cdk/tree): simplify code in lifecycle hooks #28124

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65ec485
refactor(cdk/tree): simplify code in lifecycle hooks
zarend Nov 14, 2023
2dac22a
refactor(cdk/tree): rename _renderNodeChanges to renderNodeChanges
zarend Nov 14, 2023
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235 changes: 135 additions & 100 deletions src/cdk/tree/tree.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -86,6 +86,18 @@ function coerceObservable<T>(data: T | Observable<T>): Observable<T> {
return data;
}

type RenderingData<T> =
| {
flattenedNodes: null;
nodeType: null;
renderNodes: T[];
}
| {
flattenedNodes: T[];
nodeType: 'nested' | 'flat';
renderNodes: [];
};

/**
* CDK tree component that connects with a data source to retrieve data of type `T` and renders
* dataNodes with hierarchy. Updates the dataNodes when new data is provided by the data source.
Expand Down Expand Up @@ -256,29 +268,13 @@ export class CdkTree<T, K = T>
private _elementRef: ElementRef<HTMLElement>,
) {}

ngOnInit() {
this._dataDiffer = this._differs.find([]).create(this.trackBy);
if (typeof ngDevMode === 'undefined' || ngDevMode) {
// Verify that Tree follows API contract of using one of TreeControl, levelAccessor or
// childrenAccessor. Throw an appropriate error if contract is not met.
let numTreeControls = 0;

if (this.treeControl) {
numTreeControls++;
}
if (this.levelAccessor) {
numTreeControls++;
}
if (this.childrenAccessor) {
numTreeControls++;
}
ngAfterContentInit() {
this._initializeKeyManager();
}

if (!numTreeControls) {
throw getTreeControlMissingError();
} else if (numTreeControls > 1) {
throw getMultipleTreeControlsError();
}
}
ngAfterContentChecked() {
this._updateDefaultNodeDefinition();
this._subscribeToDataChanges();
}

ngOnDestroy() {
Expand All @@ -298,51 +294,17 @@ export class CdkTree<T, K = T>
}
}

ngAfterContentInit() {
const items = combineLatest([this._keyManagerNodes, this._nodes]).pipe(
map(([keyManagerNodes, renderNodes]) =>
keyManagerNodes.reduce<CdkTreeNode<T, K>[]>((items, data) => {
const node = renderNodes.get(this._getExpansionKey(data));
if (node) {
items.push(node);
}
return items;
}, []),
),
);

const keyManagerOptions: TreeKeyManagerOptions<CdkTreeNode<T, K>> = {
trackBy: node => this._getExpansionKey(node.data),
skipPredicate: node => !!node.isDisabled,
typeAheadDebounceInterval: true,
horizontalOrientation: this._dir.value,
};

this._keyManager = this._keyManagerFactory(items, keyManagerOptions);

this._keyManager.change
.pipe(startWith(null), pairwise(), takeUntil(this._onDestroy))
.subscribe(([prev, next]) => {
prev?._setTabUnfocusable();
next?._setTabFocusable();
});

this._keyManager.change.pipe(startWith(null), takeUntil(this._onDestroy)).subscribe(() => {
// refresh the tabindex when the active item changes.
this._setTabIndex();
});
ngOnInit() {
this._checkTreeControlUsage();
this._initializeDataDiffer();
}

ngAfterContentChecked() {
private _updateDefaultNodeDefinition() {
const defaultNodeDefs = this._nodeDefs.filter(def => !def.when);
if (defaultNodeDefs.length > 1 && (typeof ngDevMode === 'undefined' || ngDevMode)) {
throw getTreeMultipleDefaultNodeDefsError();
}
this._defaultNodeDef = defaultNodeDefs[0];

if (this.dataSource && this._nodeDefs && !this._dataSubscription) {
this._observeRenderChanges();
}
}

/**
Expand Down Expand Up @@ -396,12 +358,16 @@ export class CdkTree<T, K = T>

this._dataSource = dataSource;
if (this._nodeDefs) {
this._observeRenderChanges();
this._subscribeToDataChanges();
}
}

/** Set up a subscription for the data provided by the data source. */
private _observeRenderChanges() {
private _subscribeToDataChanges() {
if (this._dataSubscription) {
return;
}

let dataStream: Observable<readonly T[]> | undefined;

if (isDataSource(this._dataSource)) {
Expand All @@ -412,6 +378,13 @@ export class CdkTree<T, K = T>
dataStream = observableOf(this._dataSource);
}

if (!dataStream) {
if (typeof ngDevMode === 'undefined' || ngDevMode) {
throw getTreeNoValidDataSourceError();
}
return;
}

let expansionModel;
if (!this.treeControl) {
this._expansionModel = new SelectionModel<K>(true);
Expand All @@ -420,49 +393,48 @@ export class CdkTree<T, K = T>
expansionModel = this.treeControl.expansionModel;
}

if (dataStream) {
this._dataSubscription = combineLatest([
dataStream,
this._nodeType,
// NB: the data is unused below, however we add it here to essentially
// trigger data rendering when expansion changes occur.
expansionModel.changed.pipe(
startWith(null),
tap(expansionChanges => {
this._emitExpansionChanges(expansionChanges);
}),
),
])
.pipe(
switchMap(([data, nodeType]) => {
if (nodeType === null) {
return observableOf([{renderNodes: data}, nodeType] as const);
}

// If we're here, then we know what our node type is, and therefore can
// perform our usual rendering pipeline, which necessitates converting the data
return this._convertData(data, nodeType).pipe(
map(convertedData => [convertedData, nodeType] as const),
);
}),
takeUntil(this._onDestroy),
)
.subscribe(([data, nodeType]) => {
this._dataSubscription = combineLatest([
dataStream,
this._nodeType,
// NB: the data is unused below, however we add it here to essentially
// trigger data rendering when expansion changes occur.
expansionModel.changed.pipe(
startWith(null),
tap(expansionChanges => {
this._emitExpansionChanges(expansionChanges);
}),
),
])
.pipe(
switchMap(([data, nodeType]) => {
if (nodeType === null) {
// Skip saving cached and key manager data.
this.renderNodeChanges(data.renderNodes);
return;
return observableOf([{renderNodes: data}, nodeType] as const);
}

// If we're here, then we know what our node type is, and therefore can
// perform our usual rendering pipeline.
this._updateCachedData(data.flattenedNodes);
this.renderNodeChanges(data.renderNodes);
this._updateKeyManagerItems(data.flattenedNodes);
});
} else if (typeof ngDevMode === 'undefined' || ngDevMode) {
throw getTreeNoValidDataSourceError();
// perform our usual rendering pipeline, which necessitates converting the data
return this._convertData(data, nodeType).pipe(
map(convertedData => [convertedData, nodeType] as const),
);
}),
takeUntil(this._onDestroy),
)
.subscribe(([data, nodeType]) => {
this._renderDataChanges({nodeType, ...data} as RenderingData<T>);
});
}

private _renderDataChanges(data: RenderingData<T>) {
if (data.nodeType === null) {
this.renderNodeChanges(data.renderNodes);
return;
}

// If we're here, then we know what our node type is, and therefore can
// perform our usual rendering pipeline.
this._updateCachedData(data.flattenedNodes);
this.renderNodeChanges(data.renderNodes);
this._updateKeyManagerItems(data.flattenedNodes);
}

private _emitExpansionChanges(expansionChanges: SelectionChange<K> | null) {
Expand All @@ -481,6 +453,69 @@ export class CdkTree<T, K = T>
}
}

private _initializeKeyManager() {
const items = combineLatest([this._keyManagerNodes, this._nodes]).pipe(
map(([keyManagerNodes, renderNodes]) =>
keyManagerNodes.reduce<CdkTreeNode<T, K>[]>((items, data) => {
const node = renderNodes.get(this._getExpansionKey(data));
if (node) {
items.push(node);
}
return items;
}, []),
),
);

const keyManagerOptions: TreeKeyManagerOptions<CdkTreeNode<T, K>> = {
trackBy: node => this._getExpansionKey(node.data),
skipPredicate: node => !!node.isDisabled,
typeAheadDebounceInterval: true,
horizontalOrientation: this._dir.value,
};

this._keyManager = this._keyManagerFactory(items, keyManagerOptions);

this._keyManager.change
.pipe(startWith(null), pairwise(), takeUntil(this._onDestroy))
.subscribe(([prev, next]) => {
prev?._setTabUnfocusable();
next?._setTabFocusable();
});

this._keyManager.change.pipe(startWith(null), takeUntil(this._onDestroy)).subscribe(() => {
// refresh the tabindex when the active item changes.
this._setTabIndex();
});
}

private _initializeDataDiffer() {
this._dataDiffer = this._differs.find([]).create(this.trackBy);
}

private _checkTreeControlUsage() {
if (typeof ngDevMode === 'undefined' || ngDevMode) {
// Verify that Tree follows API contract of using one of TreeControl, levelAccessor or
// childrenAccessor. Throw an appropriate error if contract is not met.
let numTreeControls = 0;

if (this.treeControl) {
numTreeControls++;
}
if (this.levelAccessor) {
numTreeControls++;
}
if (this.childrenAccessor) {
numTreeControls++;
}

if (!numTreeControls) {
throw getTreeControlMissingError();
} else if (numTreeControls > 1) {
throw getMultipleTreeControlsError();
}
}
}

/** Check for changes made in the data and render each change (node added/removed/moved). */
renderNodeChanges(
data: readonly T[],
Expand Down