23234668324

Committed 18 Mar 2026 07:42AM UTC coverage: 99.339% (+0.002%) from 99.337%

Build # 23234668324

Build Type

push

github

Committed by

emonkak

Commit Message

chore(test): improve naming consistency

Coverage Stats

460 of 461 branches covered (99.78%)

Branch coverage included in aggregate %.

2848 of 2869 relevant lines covered (99.27%)

508.1 hits per line

Source File
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98.9

/src/render-session.ts

import { areDependenciesChanged } from './compare.js';
import {
  $hook,
  type ActionDispatcher,
  BoundaryType,
  type Cleanup,
  type Coroutine,
  DETACHED_SCOPE,
  type Effect,
  type EffectHandler,
  type EffectQueue,
  type ErrorHandler,
  type Hook,
  type HookClass,
  type HookFunction,
  type HookObject,
  HookType,
  type InitialState,
  type NextState,
  type ReducerReturn,
  type RefObject,
  type RenderContext,
  type RenderFrame,
  type Scope,
  type SessionContext,
  type StateOptions,
  type StateReturn,
  type TemplateMode,
  type UpdateHandle,
  type UpdateOptions,
  type UpdateResult,
  type Usable,
} from './core.js';
import { DirectiveSpecifier } from './directive.js';
import { AbortError, handleError, InterruptError } from './error.js';
import { getSchedulingLanes, NoLanes } from './lane.js';

const DETACHED_HOOKS = Object.freeze([] as Hook[]) as Hook[];

export class RenderSession implements RenderContext {
  private _hooks: Hook[];

  private _hookIndex = 0;

  private readonly _frame: RenderFrame;

  private _scope: Scope;

  private readonly _coroutine: Coroutine;

  private readonly _context: SessionContext;

  constructor(
    hooks: Hook[],
    frame: RenderFrame,
    scope: Scope,
    coroutine: Coroutine,
    context: SessionContext,
  ) {
    this._hooks = hooks;
    this._frame = frame;
    this._scope = scope;
    this._coroutine = coroutine;
    this._context = context;
  }

  catchError(handler: ErrorHandler): void {
    this._scope.boundary = {
      type: BoundaryType.Error,
      next: this._scope.boundary,
      handler,
    };
  }

  finalize(): void {
    let currentHook = this._hooks[this._hookIndex];

    if (currentHook !== undefined) {
      ensureHookType<Hook.FinalizerHook>(HookType.Finalizer, currentHook);
    } else {
      currentHook = { type: HookType.Finalizer };
    }

    this._hooks[this._hookIndex] = currentHook;

    // Refuse to use new hooks after finalization.
    Object.freeze(this._hooks);

    // Refuse to mutate scope after finalization.
    Object.freeze(this._scope);

    this._scope = DETACHED_SCOPE;
    this._hooks = DETACHED_HOOKS;
    this._hookIndex = 0;
  }

  forceUpdate(options?: UpdateOptions): UpdateHandle {
    if (isDetachedScope(this._coroutine.scope)) {
      const skipped = Promise.resolve<UpdateResult>({ status: 'skipped' });
      return {
        id: -1,
        lanes: NoLanes,
        scheduled: skipped,
        finished: skipped,
      };
    }

    const renderLanes = this._frame.lanes;

    if (renderLanes !== NoLanes) {
      // We reuse the frame only for updates within the same lanes, which
      // avoids scheduling a new update during rendering. This is generally
      // undesirable, but necessary when an ErrorBoundary catches an error and
      // sets new state.
      const requestLanes = getSchedulingLanes(options ?? {});

      if ((renderLanes & requestLanes) === requestLanes) {
        for (const { id, controller } of this._context.getScheduledUpdates()) {
          if (id === this._frame.id) {
            this._frame.coroutines.push(this._coroutine);
            this._coroutine.pendingLanes |= renderLanes;
            return {
              id,
              lanes: renderLanes,
              scheduled: Promise.resolve({ status: 'skipped' }),
              finished: controller.promise,
            };
          }
        }
      }
    }

    return this._context.scheduleUpdate(this._coroutine, options);
  }

  getSessionContext(): SessionContext {
    return this._context;
  }

  getSharedContext<T>(key: unknown): T | undefined {
    let currentScope: Scope | null = this._scope;
    while (true) {
      for (
        let boundary = currentScope.boundary;
        boundary !== null;
        boundary = boundary.next
      ) {
        if (
          boundary.type === BoundaryType.SharedContext &&
          Object.is(boundary.key, key)
        ) {
          return boundary.value as T;
        }
      }
      if (currentScope.owner === null) {
        break;
      }
      currentScope = currentScope.owner.scope;
    }
    return undefined;
  }

  html(
    strings: readonly string[],
    ...values: readonly unknown[]
  ): DirectiveSpecifier<readonly unknown[]> {
    return this._createTemplate(strings, values, 'html');
  }

  interrupt(error: unknown): never {
    try {
      handleError(error, this._coroutine.scope);
    } catch (error) {
      throw new AbortError(
        this._coroutine,
        'No error boundary captured the error.',
        { cause: error },
      );
    }
    throw new InterruptError(
      this._coroutine,
      'The error was captured by an error boundary.',
      { cause: error },
    );
  }

  math(
    strings: readonly string[],
    ...values: readonly unknown[]
  ): DirectiveSpecifier<readonly unknown[]> {
    return this._createTemplate(strings, values, 'math');
  }

  setSharedContext<T>(key: unknown, value: T): void {
    this._scope.boundary = {
      type: BoundaryType.SharedContext,
      next: this._scope.boundary,
      key,
      value,
    };
  }

  startTransition<T>(action: (transition: number) => T): T {
    return this._context.startTransition((transition) => {
      const result = action(transition);
      if (result instanceof Promise) {
        result.catch((error) => {
          this.interrupt(error);
        });
      }
      return result;
    });
  }

  svg(
    strings: readonly string[],
    ...values: readonly unknown[]
  ): DirectiveSpecifier<readonly unknown[]> {
    return this._createTemplate(strings, values, 'svg');
  }

  text(
    strings: readonly string[],
    ...values: readonly unknown[]
  ): DirectiveSpecifier<readonly unknown[]> {
    return this._createTemplate(strings, values, 'textarea');
  }

  use<T>(usable: HookClass<T>): T;
  use<T>(usable: HookObject<T>): T;
  use<T>(usable: HookFunction<T>): T;
  use<T>(usable: Usable<T>): T {
    if ($hook in usable) {
      return usable[$hook](this);
    } else {
      return usable(this);
    }
  }

  useCallback<TCallback extends (...args: any[]) => any>(
    callback: TCallback,
    dependencies: readonly unknown[],
  ): TCallback {
    return this.useMemo(() => callback, dependencies);
  }

  useEffect(
    setup: () => Cleanup | void,
    dependencies: readonly unknown[] | null = null,
  ): void {
    this._useEffectHook(
      setup,
      dependencies,
      HookType.PassiveEffect,
      this._frame.passiveEffects,
    );
  }

  useId(): string {
    let currentHook = this._hooks[this._hookIndex];

    if (currentHook !== undefined) {
      ensureHookType<Hook.IdHook>(HookType.Id, currentHook);
    } else {
      currentHook = {
        type: HookType.Id,
        id: this._context.nextIdentifier(),
      };
    }

    this._hooks[this._hookIndex] = currentHook;
    this._hookIndex++;

    return currentHook.id;
  }

  useInsertionEffect(
    setup: () => Cleanup | void,
    dependencies: readonly unknown[] | null = null,
  ): void {
    this._useEffectHook(
      setup,
      dependencies,
      HookType.InsertionEffect,
      this._frame.mutationEffects,
    );
  }

  useLayoutEffect(
    setup: () => Cleanup | void,
    dependencies: readonly unknown[] | null = null,
  ): void {
    this._useEffectHook(
      setup,
      dependencies,
      HookType.LayoutEffect,
      this._frame.layoutEffects,
    );
  }

  useMemo<TResult>(
    computation: () => TResult,
    dependencies: readonly unknown[],
  ): TResult {
    let currentHook = this._hooks[this._hookIndex];

    if (currentHook !== undefined) {
      ensureHookType<Hook.MemoHook<TResult>>(HookType.Memo, currentHook);

      if (
        areDependenciesChanged(dependencies, currentHook.memoizedDependencies)
      ) {
        currentHook = {
          type: HookType.Memo,
          memoizedResult: computation(),
          memoizedDependencies: dependencies,
        };
      }
    } else {
      currentHook = {
        type: HookType.Memo,
        memoizedResult: computation(),
        memoizedDependencies: dependencies,
      };
    }

    this._hooks[this._hookIndex] = currentHook;
    this._hookIndex++;

    return currentHook.memoizedResult as TResult;
  }

  useReducer<TState, TAction>(
    reducer: (state: TState, action: TAction) => TState,
    initialState: InitialState<TState>,
    options?: StateOptions,
  ): ReducerReturn<TState, TAction> {
    const { memoizedProposals, dispatcher } = this._useReducerHook(
      reducer,
      initialState,
      options,
    );
    return [
      dispatcher.pendingState,
      dispatcher.dispatch,
      memoizedProposals.length > 0,
    ];
  }

  useRef<T>(initialValue: T): RefObject<T> {
    return this.useMemo(() => Object.seal({ current: initialValue }), []);
  }

  useState<TState>(
    initialState: InitialState<TState>,
    options?: StateOptions,
  ): StateReturn<TState> {
    const { memoizedProposals, dispatcher } = this._useReducerHook<
      TState,
      NextState<TState>
    >(
      (state, action) =>
        typeof action === 'function'
          ? (action as (prevState: TState) => TState)(state)
          : action,
      initialState,
      options,
    );
    return [
      dispatcher.pendingState,
      dispatcher.dispatch,
      memoizedProposals.length > 0,
    ];
  }

  private _createTemplate(
    strings: readonly string[],
    values: readonly unknown[],
    mode: TemplateMode,
  ): DirectiveSpecifier<readonly unknown[]> {
    const template = this._context.resolveTemplate(strings, values, mode);
    return new DirectiveSpecifier(template, values);
  }

  private _useEffectHook(
    setup: () => Cleanup | void,
    dependencies: readonly unknown[] | null,
    type: Hook.EffectHook['type'],
    queue: EffectQueue,
  ): void {
    let currentHook = this._hooks[this._hookIndex];

    if (currentHook !== undefined) {
      ensureHookType<Hook.EffectHook>(type, currentHook);
      const { handler, memoizedDependencies } = currentHook;
      if (areDependenciesChanged(dependencies, memoizedDependencies)) {
        handler.epoch++;
        queue.push(new InvokeEffect(handler), this._scope.level);
        currentHook = {
          type,
          handler,
          memoizedDependencies: dependencies,
        };
      }
      handler.setup = setup;
    } else {
      const handler: EffectHandler = {
        setup,
        cleanup: undefined,
        epoch: 0,
      };
      currentHook = {
        type,
        handler,
        memoizedDependencies: dependencies,
      };
      queue.push(new InvokeEffect(handler), this._scope.level);
    }

    this._hooks[this._hookIndex] = currentHook;
    this._hookIndex++;
  }

  private _useReducerHook<TState, TAction>(
    reducer: (state: TState, action: TAction) => TState,
    initialState: InitialState<TState>,
    options: StateOptions = {},
  ): Hook.ReducerHook<TState, TAction> {
    let currentHook = this._hooks[this._hookIndex];

    if (currentHook !== undefined) {
      ensureHookType<Hook.ReducerHook<TState, TAction>>(
        HookType.Reducer,
        currentHook,
      );

      const { dispatcher, memoizedState, memoizedProposals } = currentHook;
      const renderLanes = this._frame.lanes;
      let newState = options.passthrough
        ? getInitialState(initialState)
        : memoizedState;
      let skipLanes = NoLanes;

      memoizedProposals.push(...dispatcher.pendingProposals);

      for (const proposal of memoizedProposals) {
        const { action, lanes, revertLanes } = proposal;
        if ((lanes & renderLanes) === lanes) {
          newState = reducer(newState, action);
          proposal.lanes = NoLanes;
        } else if ((revertLanes & renderLanes) === revertLanes) {
          skipLanes |= lanes;
        }
      }

      if (skipLanes === NoLanes) {
        currentHook = {
          type: HookType.Reducer,
          dispatcher,
          memoizedState: newState,
          memoizedProposals: [],
        };
      }

      dispatcher.context = this;
      dispatcher.pendingState = newState;
      dispatcher.pendingProposals = [];
      dispatcher.reducer = reducer;
    } else {
      const dispatcher: ActionDispatcher<TState, TAction> = {
        context: this,
        dispatch(action, options = {}) {
          const { context, pendingProposals, pendingState, reducer } = this;

          if (pendingProposals.length === 0) {
            const areStatesEqual = options.areStatesEqual ?? Object.is;
            const newState = reducer(pendingState, action);

            if (areStatesEqual(newState, pendingState)) {
              const skipped = Promise.resolve<UpdateResult>({
                status: 'skipped',
              });
              return {
                id: -1,
                lanes: NoLanes,
                scheduled: skipped,
                finished: skipped,
              };
            }
          }

          const handle = context.forceUpdate(options);
          pendingProposals.push({
            action,
            lanes: handle.lanes,
            revertLanes: options.transient ? handle.lanes : NoLanes,
          });
          return handle;
        },
        pendingProposals: [],
        pendingState: getInitialState(initialState),
        reducer,
      };
      dispatcher.dispatch = dispatcher.dispatch.bind(dispatcher);
      currentHook = {
        type: HookType.Reducer,
        memoizedState: dispatcher.pendingState,
        memoizedProposals: [],
        dispatcher,
      };
    }

    this._hooks[this._hookIndex] = currentHook;
    this._hookIndex++;

    return currentHook;
  }
}

class InvokeEffect implements Effect {
  private readonly _handler: EffectHandler;

  private readonly _epoch: number;

  constructor(handler: EffectHandler) {
    this._handler = handler;
    this._epoch = handler.epoch;
  }

  commit(): void {
    const { cleanup, epoch, setup } = this._handler;

    if (epoch === this._epoch) {
      cleanup?.();
      this._handler.cleanup = setup();
    }
  }
}

function ensureHookType<TExpectedHook extends Hook>(
  expectedType: TExpectedHook['type'],
  hook: Hook,
): asserts hook is TExpectedHook {
  if (hook.type !== expectedType) {
    throw new Error(
      `Unexpected hook type. Expected "${expectedType}" but got "${hook.type}".`,
    );
  }
}

function getInitialState<TState>(initialState: InitialState<TState>): TState {
  return typeof initialState === 'function'
    ? (initialState as () => TState)()
    : initialState;
}

function isDetachedScope(scope: Scope): boolean {
  let currentScope: Scope | undefined = scope;
  do {
    if (currentScope === DETACHED_SCOPE) {
      return true;
    }
    currentScope = currentScope.owner?.scope;
  } while (currentScope !== undefined);
  return false;
}

1	import { areDependenciesChanged } from './compare.js';
2	import {
3	$hook,
4	type ActionDispatcher,
5	BoundaryType,
6	type Cleanup,
7	type Coroutine,
8	DETACHED_SCOPE,
9	type Effect,
10	type EffectHandler,
11	type EffectQueue,
12	type ErrorHandler,
13	type Hook,
14	type HookClass,
15	type HookFunction,
16	type HookObject,
17	HookType,
18	type InitialState,
19	type NextState,
20	type ReducerReturn,
21	type RefObject,
22	type RenderContext,
23	type RenderFrame,
24	type Scope,
25	type SessionContext,
26	type StateOptions,
27	type StateReturn,
28	type TemplateMode,
29	type UpdateHandle,
30	type UpdateOptions,
31	type UpdateResult,
32	type Usable,
33	} from './core.js';
34	import { DirectiveSpecifier } from './directive.js';
35	import { AbortError, handleError, InterruptError } from './error.js';
36	import { getSchedulingLanes, NoLanes } from './lane.js';
37
38	const DETACHED_HOOKS = Object.freeze([] as Hook[]) as Hook[];	46✔
39
40	export class RenderSession implements RenderContext {
41	private _hooks: Hook[];
42
43	private _hookIndex = 0;	242✔
44
45	private readonly _frame: RenderFrame;
46
47	private _scope: Scope;
48
49	private readonly _coroutine: Coroutine;
50
51	private readonly _context: SessionContext;
52
53	constructor(
54	hooks: Hook[],
55	frame: RenderFrame,
56	scope: Scope,
57	coroutine: Coroutine,
58	context: SessionContext,
59	) {
60	this._hooks = hooks;	242✔
61	this._frame = frame;	242✔
62	this._scope = scope;	242✔
63	this._coroutine = coroutine;	242✔
64	this._context = context;	242✔
65	}
66
67	catchError(handler: ErrorHandler): void {
68	this._scope.boundary = {	27✔
69	type: BoundaryType.Error,
70	next: this._scope.boundary,
71	handler,
72	};
73	}
74
75	finalize(): void {
76	let currentHook = this._hooks[this._hookIndex];	223✔
77
78	if (currentHook !== undefined) {	223✔
79	ensureHookType<Hook.FinalizerHook>(HookType.Finalizer, currentHook);	87✔
80	} else {
81	currentHook = { type: HookType.Finalizer };	136✔
82	}
83
84	this._hooks[this._hookIndex] = currentHook;	222✔
85
86	// Refuse to use new hooks after finalization.
87	Object.freeze(this._hooks);	222✔
88
89	// Refuse to mutate scope after finalization.
90	Object.freeze(this._scope);	222✔
91
92	this._scope = DETACHED_SCOPE;	222✔
93	this._hooks = DETACHED_HOOKS;	222✔
94	this._hookIndex = 0;	222✔
95	}
96
97	forceUpdate(options?: UpdateOptions): UpdateHandle {
98	if (isDetachedScope(this._coroutine.scope)) {	41✔
99	const skipped = Promise.resolve<UpdateResult>({ status: 'skipped' });	2✔
100	return {	2✔
101	id: -1,
102	lanes: NoLanes,
103	scheduled: skipped,
104	finished: skipped,
105	};
106	}
107
108	const renderLanes = this._frame.lanes;	39✔
109
110	if (renderLanes !== NoLanes) {	39✔
111	// We reuse the frame only for updates within the same lanes, which
112	// avoids scheduling a new update during rendering. This is generally
113	// undesirable, but necessary when an ErrorBoundary catches an error and
114	// sets new state.
115	const requestLanes = getSchedulingLanes(options ?? {});	7✔
116
117	if ((renderLanes & requestLanes) === requestLanes) {	7✔
118	for (const { id, controller } of this._context.getScheduledUpdates()) {	6✔
119	if (id === this._frame.id) {	6✔
120	this._frame.coroutines.push(this._coroutine);	6✔
121	this._coroutine.pendingLanes \|= renderLanes;	6✔
122	return {	6✔
123	id,
124	lanes: renderLanes,
125	scheduled: Promise.resolve({ status: 'skipped' }),
126	finished: controller.promise,
127	};
128	}
129	}
130	}
131	}
132
133	return this._context.scheduleUpdate(this._coroutine, options);	33✔
134	}
135
136	getSessionContext(): SessionContext {
137	return this._context;	10✔
138	}
139
140	getSharedContext<T>(key: unknown): T \| undefined {
141	let currentScope: Scope \| null = this._scope;	80✔
142	while (true) {	80✔
143	for (	115✔
144	let boundary = currentScope.boundary;	115✔
145	boundary !== null;
146	boundary = boundary.next
147	) {
148	if (	109✔
149	boundary.type === BoundaryType.SharedContext &&
150	Object.is(boundary.key, key)
151	) {
152	return boundary.value as T;	77✔
153	}
154	}
155	if (currentScope.owner === null) {	38✔
156	break;	3✔
157	}
158	currentScope = currentScope.owner.scope;	35✔
159	}
160	return undefined;	3✔
161	}
162
163	html(
164	strings: readonly string[],
165	...values: readonly unknown[]
166	): DirectiveSpecifier<readonly unknown[]> {
167	return this._createTemplate(strings, values, 'html');	35✔
168	}
169
170	interrupt(error: unknown): never {
171	try {	3✔
172	handleError(error, this._coroutine.scope);	3✔
173	} catch (error) {
174	throw new AbortError(	1✔
175	this._coroutine,
176	'No error boundary captured the error.',
177	{ cause: error },
178	);
179	}
180	throw new InterruptError(	2✔
181	this._coroutine,
182	'The error was captured by an error boundary.',
183	{ cause: error },
184	);
185	}
186
187	math(
188	strings: readonly string[],
189	...values: readonly unknown[]
190	): DirectiveSpecifier<readonly unknown[]> {
191	return this._createTemplate(strings, values, 'math');	2✔
192	}
193
194	setSharedContext<T>(key: unknown, value: T): void {
195	this._scope.boundary = {	70✔
196	type: BoundaryType.SharedContext,
197	next: this._scope.boundary,
198	key,
199	value,
200	};
201	}
202
203	startTransition<T>(action: (transition: number) => T): T {
204	return this._context.startTransition((transition) => {	3✔
205	const result = action(transition);	3✔
206	if (result instanceof Promise) {	3✔
207	result.catch((error) => {	×
208	this.interrupt(error);	×
209	});
210	}
211	return result;	3✔
212	});
213	}
214
215	svg(
216	strings: readonly string[],
217	...values: readonly unknown[]
218	): DirectiveSpecifier<readonly unknown[]> {
219	return this._createTemplate(strings, values, 'svg');	2✔
220	}
221
222	text(
223	strings: readonly string[],
224	...values: readonly unknown[]
225	): DirectiveSpecifier<readonly unknown[]> {
226	return this._createTemplate(strings, values, 'textarea');	1✔
227	}
228
229	use<T>(usable: HookClass<T>): T;
230	use<T>(usable: HookObject<T>): T;
231	use<T>(usable: HookFunction<T>): T;
232	use<T>(usable: Usable<T>): T {
233	if ($hook in usable) {	237✔
234	return usable[$hook](this);	142✔
235	} else {
236	return usable(this);	95✔
237	}
238	}
239
240	useCallback<TCallback extends (...args: any[]) => any>(
241	callback: TCallback,
242	dependencies: readonly unknown[],
243	): TCallback {
244	return this.useMemo(() => callback, dependencies);	3✔
245	}
246
247	useEffect(
248	setup: () => Cleanup \| void,
249	dependencies: readonly unknown[] \| null = null,
250	): void {
251	this._useEffectHook(	70✔
252	setup,
253	dependencies,
254	HookType.PassiveEffect,
255	this._frame.passiveEffects,
256	);
257	}
258
259	useId(): string {
260	let currentHook = this._hooks[this._hookIndex];	5✔
261
262	if (currentHook !== undefined) {	5✔
263	ensureHookType<Hook.IdHook>(HookType.Id, currentHook);	3✔
264	} else {
265	currentHook = {	2✔
266	type: HookType.Id,
267	id: this._context.nextIdentifier(),
268	};
269	}
270
271	this._hooks[this._hookIndex] = currentHook;	4✔
272	this._hookIndex++;	4✔
273
274	return currentHook.id;	4✔
275	}
276
277	useInsertionEffect(
278	setup: () => Cleanup \| void,
279	dependencies: readonly unknown[] \| null = null,
280	): void {
281	this._useEffectHook(	27✔
282	setup,
283	dependencies,
284	HookType.InsertionEffect,
285	this._frame.mutationEffects,
286	);
287	}
288
289	useLayoutEffect(
290	setup: () => Cleanup \| void,
291	dependencies: readonly unknown[] \| null = null,
292	): void {
293	this._useEffectHook(	143✔
294	setup,
295	dependencies,
296	HookType.LayoutEffect,
297	this._frame.layoutEffects,
298	);
299	}
300
301	useMemo<TResult>(
302	computation: () => TResult,
303	dependencies: readonly unknown[],
304	): TResult {
305	let currentHook = this._hooks[this._hookIndex];	102✔
306
307	if (currentHook !== undefined) {	102✔
308	ensureHookType<Hook.MemoHook<TResult>>(HookType.Memo, currentHook);	63✔
309
310	if (	63✔
311	areDependenciesChanged(dependencies, currentHook.memoizedDependencies)
312	) {
313	currentHook = {	3✔
314	type: HookType.Memo,
315	memoizedResult: computation(),
316	memoizedDependencies: dependencies,
317	};
318	}
319	} else {
320	currentHook = {	39✔
321	type: HookType.Memo,
322	memoizedResult: computation(),
323	memoizedDependencies: dependencies,
324	};
325	}
326
327	this._hooks[this._hookIndex] = currentHook;	101✔
328	this._hookIndex++;	101✔
329
330	return currentHook.memoizedResult as TResult;	101✔
331	}
332
333	useReducer<TState, TAction>(
334	reducer: (state: TState, action: TAction) => TState,
335	initialState: InitialState<TState>,
336	options?: StateOptions,
337	): ReducerReturn<TState, TAction> {
338	const { memoizedProposals, dispatcher } = this._useReducerHook(	5✔
339	reducer,
340	initialState,
341	options,
342	);
343	return [	5✔
344	dispatcher.pendingState,
345	dispatcher.dispatch,
346	memoizedProposals.length > 0,
347	];
348	}
349
350	useRef<T>(initialValue: T): RefObject<T> {
351	return this.useMemo(() => Object.seal({ current: initialValue }), []);	9✔
352	}
353
354	useState<TState>(
355	initialState: InitialState<TState>,
356	options?: StateOptions,
357	): StateReturn<TState> {
358	const { memoizedProposals, dispatcher } = this._useReducerHook<	76✔
359	TState,
360	NextState<TState>
361	>(
362	(state, action) =>
363	typeof action === 'function'	49✔
364	? (action as (prevState: TState) => TState)(state)
365	: action,
366	initialState,
367	options,
368	);
369	return [	76✔
370	dispatcher.pendingState,
371	dispatcher.dispatch,
372	memoizedProposals.length > 0,
373	];
374	}
375
376	private _createTemplate(
377	strings: readonly string[],
378	values: readonly unknown[],
379	mode: TemplateMode,
380	): DirectiveSpecifier<readonly unknown[]> {
381	const template = this._context.resolveTemplate(strings, values, mode);	40✔
382	return new DirectiveSpecifier(template, values);	40✔
383	}
384
385	private _useEffectHook(
386	setup: () => Cleanup \| void,
387	dependencies: readonly unknown[] \| null,
388	type: Hook.EffectHook['type'],
389	queue: EffectQueue,
390	): void {
391	let currentHook = this._hooks[this._hookIndex];	240✔
392
393	if (currentHook !== undefined) {	240✔
394	ensureHookType<Hook.EffectHook>(type, currentHook);	96✔
395	const { handler, memoizedDependencies } = currentHook;	96✔
396	if (areDependenciesChanged(dependencies, memoizedDependencies)) {	96✔
397	handler.epoch++;	21✔
398	queue.push(new InvokeEffect(handler), this._scope.level);	21✔
399	currentHook = {	21✔
400	type,
401	handler,
402	memoizedDependencies: dependencies,
403	};
404	}
405	handler.setup = setup;	93✔
406	} else {
407	const handler: EffectHandler = {	144✔
408	setup,
409	cleanup: undefined,
410	epoch: 0,
411	};
412	currentHook = {	144✔
413	type,
414	handler,
415	memoizedDependencies: dependencies,
416	};
417	queue.push(new InvokeEffect(handler), this._scope.level);	144✔
418	}
419
420	this._hooks[this._hookIndex] = currentHook;	237✔
421	this._hookIndex++;	237✔
422	}
423
424	private _useReducerHook<TState, TAction>(
425	reducer: (state: TState, action: TAction) => TState,
426	initialState: InitialState<TState>,
427	options: StateOptions = {},
428	): Hook.ReducerHook<TState, TAction> {
429	let currentHook = this._hooks[this._hookIndex];	81✔
430
431	if (currentHook !== undefined) {	81✔
432	ensureHookType<Hook.ReducerHook<TState, TAction>>(	41✔
433	HookType.Reducer,
434	currentHook,
435	);
436
437	const { dispatcher, memoizedState, memoizedProposals } = currentHook;	41✔
438	const renderLanes = this._frame.lanes;	41✔
439	let newState = options.passthrough	41✔
440	? getInitialState(initialState)
441	: memoizedState;
442	let skipLanes = NoLanes;	41✔
443
444	memoizedProposals.push(...dispatcher.pendingProposals);	41✔
445
446	for (const proposal of memoizedProposals) {	41✔
447	const { action, lanes, revertLanes } = proposal;	25✔
448	if ((lanes & renderLanes) === lanes) {	25✔
449	newState = reducer(newState, action);	24✔
450	proposal.lanes = NoLanes;	24✔
451	} else if ((revertLanes & renderLanes) === revertLanes) {	1✔
452	skipLanes \|= lanes;	1✔
453	}
454	}
455
456	if (skipLanes === NoLanes) {	40✔
457	currentHook = {	39✔
458	type: HookType.Reducer,
459	dispatcher,
460	memoizedState: newState,
461	memoizedProposals: [],
462	};
463	}
464
465	dispatcher.context = this;	40✔
466	dispatcher.pendingState = newState;	40✔
467	dispatcher.pendingProposals = [];	40✔
468	dispatcher.reducer = reducer;	40✔
469	} else {
470	const dispatcher: ActionDispatcher<TState, TAction> = {	40✔
471	context: this,
472	dispatch(action, options = {}) {
473	const { context, pendingProposals, pendingState, reducer } = this;	29✔
474
475	if (pendingProposals.length === 0) {	29✔
476	const areStatesEqual = options.areStatesEqual ?? Object.is;	28✔
477	const newState = reducer(pendingState, action);	28✔
478
479	if (areStatesEqual(newState, pendingState)) {	28✔
480	const skipped = Promise.resolve<UpdateResult>({	4✔
481	status: 'skipped',
482	});
483	return {	4✔
484	id: -1,
485	lanes: NoLanes,
486	scheduled: skipped,
487	finished: skipped,
488	};
489	}
490	}
491
492	const handle = context.forceUpdate(options);	25✔
493	pendingProposals.push({	25✔
494	action,
495	lanes: handle.lanes,
496	revertLanes: options.transient ? handle.lanes : NoLanes,
497	});
498	return handle;	29✔
499	},
500	pendingProposals: [],
501	pendingState: getInitialState(initialState),
502	reducer,
503	};
504	dispatcher.dispatch = dispatcher.dispatch.bind(dispatcher);	40✔
505	currentHook = {	40✔
506	type: HookType.Reducer,
507	memoizedState: dispatcher.pendingState,
508	memoizedProposals: [],
509	dispatcher,
510	};
511	}
512
513	this._hooks[this._hookIndex] = currentHook;	80✔
514	this._hookIndex++;	80✔
515
516	return currentHook;	80✔
517	}
518	}
519
520	class InvokeEffect implements Effect {
521	private readonly _handler: EffectHandler;
522
523	private readonly _epoch: number;
524
525	constructor(handler: EffectHandler) {
526	this._handler = handler;	165✔
527	this._epoch = handler.epoch;	165✔
528	}
529
530	commit(): void {
531	const { cleanup, epoch, setup } = this._handler;	164✔
532
533	if (epoch === this._epoch) {	164✔
534	cleanup?.();	161✔
535	this._handler.cleanup = setup();	161✔
536	}
537	}
538	}
539
540	function ensureHookType<TExpectedHook extends Hook>(
541	expectedType: TExpectedHook['type'],
542	hook: Hook,
543	): asserts hook is TExpectedHook {
544	if (hook.type !== expectedType) {	290✔
545	throw new Error(	7✔
546	`Unexpected hook type. Expected "${expectedType}" but got "${hook.type}".`,
547	);
548	}
549	}
550
551	function getInitialState<TState>(initialState: InitialState<TState>): TState {
552	return typeof initialState === 'function'	40✔
553	? (initialState as () => TState)()
554	: initialState;
555	}
556
557	function isDetachedScope(scope: Scope): boolean {
558	let currentScope: Scope \| undefined = scope;	41✔
559	do {	41✔
560	if (currentScope === DETACHED_SCOPE) {	52✔
561	return true;	2✔
562	}
563	currentScope = currentScope.owner?.scope;	50✔
564	} while (currentScope !== undefined);
565	return false;	39✔
566	}

emonkak / barebind / 23234668324

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