27772560676

Committed 18 Jun 2026 04:00PM UTC coverage: 70.602% (-24.4%) from 95.043%

Build # 27772560676

Build Type

push

github

Committed by

emonkak

Commit Message

refactor(runtime): simplify node reconstruction using spread operator

Coverage Stats

187 of 261 branches covered (71.65%)

Branch coverage included in aggregate %.

1045 of 1484 relevant lines covered (70.42%)

51.99 hits per line

Source File
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98.25

/src/runtime.ts

import {
  type Commit,
  type Dispatcher,
  type HostAdapter,
  type Lanes,
  MUTATION_TYPE_INSERT,
  MUTATION_TYPE_REMOVE,
  MUTATION_TYPE_UPDATE,
  MUTATION_TYPE_UPDATE_AND_MOVE,
  type Part,
  type Renderer,
  type RenderNode,
  type RenderRoot,
  type Scope,
  type UpdateHandle,
  type UpdateOptions,
  type UpdateUnit,
  VBind,
  VComponent,
  type VElement,
  VFragment,
  VPortal,
  VTemplate,
} from './core.js';
import { assertUnreachable } from './debug.js';
import {
  getHighestPriorityLane,
  getLaneFromPriority,
  getPriorityFromLanes,
  getRenderLanes,
  NoLanes,
  SyncLane,
  ViewTransitionLane,
} from './lane.js';
import { PriorityQueue } from './queue.js';

interface Update {
  id: number;
  lanes: Lanes;
  unit: UpdateUnit;
  controller: PromiseWithResolvers<void>;
}

export class Runtime implements Renderer, Dispatcher {
  /** @internal */
  readonly _adapter: HostAdapter;
  /** @internal */
  readonly _updateQueue: PriorityQueue<Update> = new PriorityQueue(
    compareUpdates,
  );
  /** @internal */
  _updateBatch: Update[] = [];
  private _pendingLanes: number = NoLanes;
  private _stagedLanes: number = NoLanes;
  private _flushLanes: number = NoLanes;
  private _identifierCount: number = 0;
  private _transitionCount: number = 0;
  private _updateCount: number = 0;

  constructor(adapter: HostAdapter) {
    this._adapter = adapter;
  }

  get flushLanes(): Lanes {
    return this._flushLanes;
  }

  diff(
    oldNode: RenderNode,
    newElement: VElement,
    scope: Scope,
    index: number,
    parent: RenderNode | RenderRoot,
  ): RenderNode {
    if (oldNode.type !== newElement.type || oldNode.key !== newElement.key) {
      return this.render(newElement, scope, index, parent, oldNode.part);
    }
    if (oldNode.props === newElement.props) {
      return oldNode;
    }
    switch (true) {
      case newElement instanceof VBind: {
        return {
          ...(oldNode as RenderNode.BindNode),
          type: newElement.type,
          props: newElement.props,
          key: newElement.key,
          dirty: true,
        };
      }
      case newElement instanceof VComponent: {
        if (
          ((oldNode as RenderNode.ComponentNode).state.handle.pendingLanes &
            this._flushLanes) ===
            NoLanes &&
          (oldNode as RenderNode.ComponentNode).type.arePropsEqual(
            oldNode.props,
            newElement.props,
          )
        ) {
          return oldNode;
        }
        const newNode: RenderNode.ComponentNode = {
          ...(oldNode as RenderNode.ComponentNode),
          type: newElement.type,
          props: newElement.props,
          key: newElement.key,
          index,
          parent,
          children: oldNode.children.slice(),
          dirty: true,
        };
        const subScope = scope.child(newElement.type);
        newNode.children[0] = this.diff(
          newNode.children[0]!,
          newNode.state.handle.render(
            newNode.props,
            subScope,
            this._flushLanes,
          ),
          subScope,
          0,
          newNode,
        );
        return newNode;
      }
      case newElement instanceof VFragment: {
        const newNode: RenderNode.FragmentNode = {
          ...(oldNode as RenderNode.FragmentNode),
          type: newElement.type,
          props: newElement.props,
          key: newElement.key,
          index,
          parent,
          children: new Array(newElement.children.length),
        };
        this._diffChildren(
          oldNode as RenderNode.FragmentNode,
          newNode,
          newElement.children,
          scope,
        );
        return newNode;
      }
      case newElement instanceof VPortal:
      case newElement instanceof VTemplate: {
        const newNode: RenderNode.BlockNode = {
          ...(oldNode as RenderNode.BlockNode),
          type: newElement.type,
          props: newElement.props,
          key: newElement.key,
          index,
          parent,
          children: new Array(newElement.children.length),
        };
        for (let i = 0, l = newElement.children.length; i < l; i++) {
          const newChild = this.diff(
            oldNode.children[i]!,
            newElement.children[i]!,
            scope,
            i,
            newNode,
          );
          newNode.children[i] = newChild;
          newNode.dirty ||= newChild.dirty;
        }
        return newNode;
      }
      default:
        /** v8 ignore next @preserve */
        DEBUG: {
          assertUnreachable(newElement);
        }
    }
  }

  nextIdentifier(): string {
    return this._adapter.getIdentifier() + '-' + this._identifierCount++;
  }

  nextTransition(): number {
    return this._transitionCount++;
  }

  render(
    element: VElement,
    scope: Scope,
    index: number,
    parent: RenderNode | RenderRoot,
    part: Part,
  ): RenderNode {
    switch (true) {
      case element instanceof VBind: {
        return {
          type: element.type,
          props: element.props,
          key: element.key,
          part,
          index,
          parent,
          children: [],
          state: null,
          dirty: true,
        };
      }
      case element instanceof VComponent: {
        const node: RenderNode.ComponentNode = {
          type: element.type,
          props: element.props,
          key: element.key,
          part,
          index,
          parent,
          children: new Array(1),
          state: {
            handle: element.type.createHandle(this),
            scope,
          },
          dirty: true,
        };
        const subScope = scope.child(element.type);
        node.children[0] = this.render(
          node.state.handle.render(node.props, subScope, this._flushLanes),
          subScope,
          0,
          node,
          part,
        );
        return node;
      }
      case element instanceof VFragment: {
        const node: RenderNode.FragmentNode = {
          type: element.type,
          props: element.props,
          key: element.key,
          part,
          index,
          parent,
          children: new Array(element.children.length),
          state: { mutations: [] },
          dirty: element.children.length > 0,
        };
        for (let i = 0, l = element.children.length; i < l; i++) {
          node.children[i] = this.render(
            element.children[i]!,
            scope,
            i,
            node,
            part,
          );
        }
        return node;
      }
      case element instanceof VPortal: {
        const block = this._adapter.renderPortal(element);
        const node: RenderNode.BlockNode = {
          type: element.type,
          props: element.props,
          key: element.key,
          part,
          index,
          parent,
          children: new Array(1),
          state: { block },
          dirty: true,
        };
        node.children[0] = this.render(
          element.children[0],
          scope,
          0,
          node,
          block.parts[0]!,
        );
        return node;
      }
      case element instanceof VTemplate: {
        const block = this._adapter.renderTemplate(element);
        const node: RenderNode.BlockNode = {
          type: element.type,
          props: element.props,
          key: element.key,
          part,
          index,
          parent,
          children: new Array(element.children.length),
          state: { block },
          dirty: true,
        };
        for (let i = 0, l = element.children.length; i < l; i++) {
          node.children[i] = this.render(
            element.children[i]!,
            scope,
            i,
            node,
            block.parts[i]!,
          );
        }
        return node;
      }
      default:
        /** v8 ignore next @preserve */
        DEBUG: {
          assertUnreachable(element);
        }
    }
  }

  schedule(unit: UpdateUnit, options: UpdateOptions = {}): UpdateHandle {
    const controller = Promise.withResolvers<void>();
    const id = this._updateCount++;
    const lanes =
      getRenderLanes(options) ||
      getLaneFromPriority(this._adapter.getTaskPriority());

    this._updateQueue.enqueue({
      id,
      lanes,
      unit,
      controller,
    });

    if (((this._pendingLanes | this._stagedLanes) & lanes) !== lanes) {
      const priority = getPriorityFromLanes(lanes);
      this._pendingLanes |= lanes;
      this._adapter.requestCallback(
        () => {
          this._pendingLanes &= ~lanes;
          this._stagedLanes |= lanes;
          if (this._flushLanes === NoLanes) {
            this._flush();
          }
        },
        { ...options, priority },
      );
    }

    return {
      id,
      lanes,
      finished: controller.promise,
    };
  }

  private _diffChildren(
    oldParent: RenderNode.FragmentNode,
    newParent: RenderNode.FragmentNode,
    newElements: VElement[],
    scope: Scope,
  ): void {
    const oldChildren: (RenderNode | undefined)[] = oldParent.children.slice();
    const newChildren = newParent.children;
    const oldKeys = oldChildren.map((child) => child!.key);
    const newKeys = newElements.map((element) => element.key);
    const mutations = newParent.state.mutations;

    let oldHead = 0;
    let newHead = 0;
    let oldTail = oldKeys.length - 1;
    let newTail = newKeys.length - 1;
    let oldKeyToIndexMap: Map<unknown, number> | undefined;
    let newKeyToIndexMap: Map<unknown, number> | undefined;

    while (true) {
      if (newHead > newTail) {
        while (oldHead <= oldTail) {
          const oldChild = oldChildren[oldHead];
          if (oldChild !== undefined) {
            mutations.push({
              type: MUTATION_TYPE_REMOVE,
              node: oldChild,
            });
          }
          oldHead++;
        }
        break;
      }
      if (oldHead > oldTail) {
        while (newHead <= newTail) {
          const newChild = this.render(
            newElements[newHead]!,
            scope,
            newHead,
            newParent,
            newParent.part,
          );
          mutations.push({
            type: MUTATION_TYPE_INSERT,
            node: newChild,
            afterNode: newChildren[newTail + 1],
          });
          newChildren[newHead] = newChild;
          newHead++;
        }
        break;
      }
      if (oldChildren[oldHead] === undefined) {
        oldHead++;
      } else if (oldChildren[oldTail] === undefined) {
        oldTail--;
      } else if (Object.is(oldKeys[oldHead]!, newKeys[newHead]!)) {
        const oldChild = oldChildren[oldHead]!;
        const newChild = this.diff(
          oldChild,
          newElements[newHead]!,
          scope,
          newHead,
          newParent,
        );
        if (oldChild !== newChild) {
          mutations.push({
            type: MUTATION_TYPE_UPDATE,
            oldNode: oldChildren[oldHead]!,
            newNode: newChild,
          });
        }
        newChildren[newHead] = newChild;
        oldHead++;
        newHead++;
      } else if (Object.is(oldKeys[oldTail]!, newKeys[newTail]!)) {
        const oldChild = oldChildren[oldTail]!;
        const newChild = this.diff(
          oldChild,
          newElements[newTail]!,
          scope,
          newTail,
          newParent,
        );
        if (oldChild !== newChild) {
          mutations.push({
            type: MUTATION_TYPE_UPDATE,
            oldNode: oldChildren[oldTail]!,
            newNode: newChild,
          });
        }
        newChildren[newTail] = newChild;
        oldTail--;
        newTail--;
      } else if (
        Object.is(oldKeys[oldHead]!, newKeys[newTail]!) &&
        Object.is(oldKeys[oldTail]!, newKeys[newHead]!)
      ) {
        const tailChild = this.diff(
          oldChildren[oldTail]!,
          newElements[newHead]!,
          scope,
          newHead,
          newParent,
        );
        const headChild = this.diff(
          oldChildren[oldHead]!,
          newElements[newTail]!,
          scope,
          newTail,
          newParent,
        );
        mutations.push({
          type: MUTATION_TYPE_UPDATE_AND_MOVE,
          oldNode: oldChildren[oldTail]!,
          newNode: tailChild,
          afterNode: oldChildren[oldHead],
        });
        mutations.push({
          type: MUTATION_TYPE_UPDATE_AND_MOVE,
          oldNode: oldChildren[oldHead]!,
          newNode: headChild,
          afterNode: newChildren[newTail + 1],
        });
        newChildren[newHead] = tailChild;
        newChildren[newTail] = headChild;
        oldHead++;
        newHead++;
        oldTail--;
        newTail--;
      } else {
        newKeyToIndexMap ??= buildKeyToIndexMap(newKeys, newHead, newTail);

        if (!newKeyToIndexMap.has(oldKeys[oldHead]!)) {
          const oldChild = oldChildren[oldHead]!;
          mutations.push({
            type: MUTATION_TYPE_REMOVE,
            node: oldChild,
          });
          oldHead++;
        } else if (!newKeyToIndexMap.has(oldKeys[oldTail]!)) {
          const oldChild = oldChildren[oldTail]!;
          mutations.push({
            type: MUTATION_TYPE_REMOVE,
            node: oldChild,
          });
          oldTail--;
        } else {
          oldKeyToIndexMap ??= buildKeyToIndexMap(oldKeys, oldHead, oldTail);
          const oldIndex = oldKeyToIndexMap.get(newKeys[newTail]!);

          if (
            oldIndex !== undefined &&
            oldIndex >= oldHead &&
            oldIndex <= oldTail &&
            oldChildren[oldIndex] !== undefined
          ) {
            const newChild = this.diff(
              oldChildren[oldIndex]!,
              newElements[newTail]!,
              scope,
              newTail,
              newParent,
            );
            mutations.push({
              type: MUTATION_TYPE_UPDATE_AND_MOVE,
              oldNode: oldChildren[oldIndex]!,
              newNode: newChild,
              afterNode: newChildren[newTail + 1],
            });
            newChildren[newTail] = newChild;
            oldChildren[oldIndex] = undefined;
          } else {
            const newChild = this.render(
              newElements[newTail]!,
              scope,
              newTail,
              newParent,
              newParent.part,
            );
            mutations.push({
              type: MUTATION_TYPE_INSERT,
              node: newChild,
              afterNode: newChildren[newTail + 1],
            });
            newChildren[newTail] = newChild;
          }

          newTail--;
        }
      }
    }

    newParent.dirty = mutations.length > 0;
  }

  private async _flush(): Promise<void> {
    while (true) {
      let update: Update | undefined;

      this._flushLanes |= this._stagedLanes;
      this._stagedLanes = NoLanes;

      while ((update = this._updateQueue.peek()) !== undefined) {
        if ((this._flushLanes & update.lanes) !== update.lanes) {
          break;
        }
        this._updateBatch.push(this._updateQueue.dequeue()!);
      }

      if (this._updateBatch.length === 0) {
        break;
      }

      try {
        const commitBatch: Commit[] = [];
        const flushSync = (this._flushLanes & SyncLane) === SyncLane;

        for (const update of this._updateBatch) {
          const { lanes, unit } = update;

          if ((unit.pendingLanes & lanes) === NoLanes) {
            continue;
          }

          if (!flushSync && commitBatch.length > 0) {
            await this._adapter.yieldToMain();
          }

          commitBatch.push(unit.prepare(this._flushLanes, this));
        }

        if (commitBatch.length > 0) {
          const commit = () => {
            for (const commit of commitBatch) {
              commit();
            }
          };
          if (flushSync) {
            commit();
          } else if (this._flushLanes & ViewTransitionLane) {
            await this._adapter.startViewTransition(commit);
          } else {
            await this._adapter.requestCommit(commit);
          }
        }

        for (const { controller } of this._updateBatch) {
          controller.resolve();
        }
      } catch (error) {
        for (const { controller } of this._updateBatch) {
          controller.reject(error);
        }
      } finally {
        this._updateBatch = [];
      }
    }

    this._flushLanes = NoLanes;
  }
}

export async function waitForStep(runtime: Runtime): Promise<boolean> {
  if (runtime._updateBatch.length > 0) {
    for (const update of runtime._updateBatch) {
      await update.controller.promise;
    }
    return true;
  } else {
    const update = runtime._updateQueue.peek();
    if (update !== undefined) {
      await update.controller.promise;
      return true;
    }
    return false;
  }
}

function buildKeyToIndexMap<T>(
  keys: T[],
  head: number,
  tail: number,
): Map<T, number> {
  const keyToIndexMap = new Map();
  for (let i = head; i <= tail; i++) {
    keyToIndexMap.set(keys[i]!, i);
  }
  return keyToIndexMap;
}

function compareUpdates(update1: Update, update2: Update): number {
  const lane1 = getHighestPriorityLane(update1.lanes);
  const lane2 = getHighestPriorityLane(update2.lanes);
  const level1 = update1.unit.level;
  const level2 = update2.unit.level;
  return lane1 !== lane2 ? lane1 - lane2 : level1 - level2;
}

1	import {
2	type Commit,
3	type Dispatcher,
4	type HostAdapter,
5	type Lanes,
6	MUTATION_TYPE_INSERT,
7	MUTATION_TYPE_REMOVE,
8	MUTATION_TYPE_UPDATE,
9	MUTATION_TYPE_UPDATE_AND_MOVE,
10	type Part,
11	type Renderer,
12	type RenderNode,
13	type RenderRoot,
14	type Scope,
15	type UpdateHandle,
16	type UpdateOptions,
17	type UpdateUnit,
18	VBind,
19	VComponent,
20	type VElement,
21	VFragment,
22	VPortal,
23	VTemplate,
24	} from './core.js';
25	import { assertUnreachable } from './debug.js';
26	import {
27	getHighestPriorityLane,
28	getLaneFromPriority,
29	getPriorityFromLanes,
30	getRenderLanes,
31	NoLanes,
32	SyncLane,
33	ViewTransitionLane,
34	} from './lane.js';
35	import { PriorityQueue } from './queue.js';
36
37	interface Update {
38	id: number;
39	lanes: Lanes;
40	unit: UpdateUnit;
41	controller: PromiseWithResolvers<void>;
42	}
43
44	export class Runtime implements Renderer, Dispatcher {
45	/** @internal */
46	readonly _adapter: HostAdapter;
47	/** @internal */
48	readonly _updateQueue: PriorityQueue<Update> = new PriorityQueue(	148✔
49	compareUpdates,
50	);
51	/** @internal */
52	_updateBatch: Update[] = [];	148✔
53	private _pendingLanes: number = NoLanes;	148✔
54	private _stagedLanes: number = NoLanes;	148✔
55	private _flushLanes: number = NoLanes;	148✔
56	private _identifierCount: number = 0;	148✔
57	private _transitionCount: number = 0;	148✔
58	private _updateCount: number = 0;	148✔
59
60	constructor(adapter: HostAdapter) {
61	this._adapter = adapter;	148✔
62	}
63
64	get flushLanes(): Lanes {
65	return this._flushLanes;	43✔
66	}
67
68	diff(
69	oldNode: RenderNode,
70	newElement: VElement,
71	scope: Scope,
72	index: number,
73	parent: RenderNode \| RenderRoot,
74	): RenderNode {
75	if (oldNode.type !== newElement.type \|\| oldNode.key !== newElement.key) {	331✔
76	return this.render(newElement, scope, index, parent, oldNode.part);	4✔
77	}
78	if (oldNode.props === newElement.props) {	327✔
79	return oldNode;	6✔
80	}
81	switch (true) {	321✔
82	case newElement instanceof VBind: {
83	return {	166✔
84	...(oldNode as RenderNode.BindNode),
85	type: newElement.type,
86	props: newElement.props,
87	key: newElement.key,
88	dirty: true,
89	};
90	}
91	case newElement instanceof VComponent: {
92	if (	11✔
93	((oldNode as RenderNode.ComponentNode).state.handle.pendingLanes &
94	this._flushLanes) ===
95	NoLanes &&
96	(oldNode as RenderNode.ComponentNode).type.arePropsEqual(
97	oldNode.props,
98	newElement.props,
99	)
100	) {
101	return oldNode;	1✔
102	}
103	const newNode: RenderNode.ComponentNode = {	10✔
104	...(oldNode as RenderNode.ComponentNode),
105	type: newElement.type,
106	props: newElement.props,
107	key: newElement.key,
108	index,
109	parent,
110	children: oldNode.children.slice(),
111	dirty: true,
112	};
113	const subScope = scope.child(newElement.type);	10✔
114	newNode.children[0] = this.diff(	10✔
115	newNode.children[0]!,
116	newNode.state.handle.render(
117	newNode.props,
118	subScope,
119	this._flushLanes,
120	),
121	subScope,
122	0,
123	newNode,
124	);
125	return newNode;	10✔
126	}
127	case newElement instanceof VFragment: {
128	const newNode: RenderNode.FragmentNode = {	25✔
129	...(oldNode as RenderNode.FragmentNode),
130	type: newElement.type,
131	props: newElement.props,
132	key: newElement.key,
133	index,
134	parent,
135	children: new Array(newElement.children.length),
136	};
137	this._diffChildren(	25✔
138	oldNode as RenderNode.FragmentNode,
139	newNode,
140	newElement.children,
141	scope,
142	);
143	return newNode;	25✔
144	}
145	case newElement instanceof VPortal:
146	case newElement instanceof VTemplate: {
147	const newNode: RenderNode.BlockNode = {	119✔
148	...(oldNode as RenderNode.BlockNode),
149	type: newElement.type,
150	props: newElement.props,
151	key: newElement.key,
152	index,
153	parent,
154	children: new Array(newElement.children.length),
155	};
156	for (let i = 0, l = newElement.children.length; i < l; i++) {	119✔
157	const newChild = this.diff(	172✔
158	oldNode.children[i]!,
159	newElement.children[i]!,
160	scope,
161	i,
162	newNode,
163	);
164	newNode.children[i] = newChild;	172✔
165	newNode.dirty \|\|= newChild.dirty;	172✔
166	}
167	return newNode;	119✔
168	}
169	default:
170	/** v8 ignore next @preserve */
171	DEBUG: {	×
172	assertUnreachable(newElement);	×
173	}
174	}
175	}
176
177	nextIdentifier(): string {
178	return this._adapter.getIdentifier() + '-' + this._identifierCount++;	2✔
179	}
180
181	nextTransition(): number {
182	return this._transitionCount++;	25✔
183	}
184
185	render(
186	element: VElement,
187	scope: Scope,
188	index: number,
189	parent: RenderNode \| RenderRoot,
190	part: Part,
191	): RenderNode {
192	switch (true) {	499✔
193	case element instanceof VBind: {
194	return {	206✔
195	type: element.type,
196	props: element.props,
197	key: element.key,
198	part,
199	index,
200	parent,
201	children: [],
202	state: null,
203	dirty: true,
204	};
205	}
206	case element instanceof VComponent: {
207	const node: RenderNode.ComponentNode = {	53✔
208	type: element.type,
209	props: element.props,
210	key: element.key,
211	part,
212	index,
213	parent,
214	children: new Array(1),
215	state: {
216	handle: element.type.createHandle(this),
217	scope,
218	},
219	dirty: true,
220	};
221	const subScope = scope.child(element.type);	53✔
222	node.children[0] = this.render(	53✔
223	node.state.handle.render(node.props, subScope, this._flushLanes),
224	subScope,
225	0,
226	node,
227	part,
228	);
229	return node;	53✔
230	}
231	case element instanceof VFragment: {
232	const node: RenderNode.FragmentNode = {	30✔
233	type: element.type,
234	props: element.props,
235	key: element.key,
236	part,
237	index,
238	parent,
239	children: new Array(element.children.length),
240	state: { mutations: [] },
241	dirty: element.children.length > 0,
242	};
243	for (let i = 0, l = element.children.length; i < l; i++) {	30✔
244	node.children[i] = this.render(	68✔
245	element.children[i]!,
246	scope,
247	i,
248	node,
249	part,
250	);
251	}
252	return node;	30✔
253	}
254	case element instanceof VPortal: {
255	const block = this._adapter.renderPortal(element);	8✔
256	const node: RenderNode.BlockNode = {	8✔
257	type: element.type,
258	props: element.props,
259	key: element.key,
260	part,
261	index,
262	parent,
263	children: new Array(1),
264	state: { block },
265	dirty: true,
266	};
267	node.children[0] = this.render(	8✔
268	element.children[0],
269	scope,
270	0,
271	node,
272	block.parts[0]!,
273	);
274	return node;	8✔
275	}
276	case element instanceof VTemplate: {
277	const block = this._adapter.renderTemplate(element);	202✔
278	const node: RenderNode.BlockNode = {	202✔
279	type: element.type,
280	props: element.props,
281	key: element.key,
282	part,
283	index,
284	parent,
285	children: new Array(element.children.length),
286	state: { block },
287	dirty: true,
288	};
289	for (let i = 0, l = element.children.length; i < l; i++) {	202✔
290	node.children[i] = this.render(	211✔
291	element.children[i]!,
292	scope,
293	i,
294	node,
295	block.parts[i]!,
296	);
297	}
298	return node;	190✔
299	}
300	default:
301	/** v8 ignore next @preserve */
302	DEBUG: {	×
303	assertUnreachable(element);	×
304	}
305	}
306	}
307
308	schedule(unit: UpdateUnit, options: UpdateOptions = {}): UpdateHandle {
309	const controller = Promise.withResolvers<void>();	256✔
310	const id = this._updateCount++;	256✔
311	const lanes =
312	getRenderLanes(options) \|\|	256✔
313	getLaneFromPriority(this._adapter.getTaskPriority());
314
315	this._updateQueue.enqueue({	256✔
316	id,
317	lanes,
318	unit,
319	controller,
320	});
321
322	if (((this._pendingLanes \| this._stagedLanes) & lanes) !== lanes) {	256✔
323	const priority = getPriorityFromLanes(lanes);	253✔
324	this._pendingLanes \|= lanes;	253✔
325	this._adapter.requestCallback(	253✔
326	() => {
327	this._pendingLanes &= ~lanes;	253✔
328	this._stagedLanes \|= lanes;	253✔
329	if (this._flushLanes === NoLanes) {	253✔
330	this._flush();	250✔
331	}
332	},
333	{ ...options, priority },
334	);
335	}
336
337	return {	256✔
338	id,
339	lanes,
340	finished: controller.promise,
341	};
342	}
343
344	private _diffChildren(
345	oldParent: RenderNode.FragmentNode,
346	newParent: RenderNode.FragmentNode,
347	newElements: VElement[],
348	scope: Scope,
349	): void {
350	const oldChildren: (RenderNode \| undefined)[] = oldParent.children.slice();	25✔
351	const newChildren = newParent.children;	25✔
352	const oldKeys = oldChildren.map((child) => child!.key);	58✔
353	const newKeys = newElements.map((element) => element.key);	61✔
354	const mutations = newParent.state.mutations;	25✔
355
356	let oldHead = 0;	25✔
357	let newHead = 0;	25✔
358	let oldTail = oldKeys.length - 1;	25✔
359	let newTail = newKeys.length - 1;	25✔
360	let oldKeyToIndexMap: Map<unknown, number> \| undefined;
361	let newKeyToIndexMap: Map<unknown, number> \| undefined;
362
363	while (true) {	25✔
364	if (newHead > newTail) {	78✔
365	while (oldHead <= oldTail) {	18✔
366	const oldChild = oldChildren[oldHead];	2✔
367	if (oldChild !== undefined) {	2✔
368	mutations.push({	1✔
369	type: MUTATION_TYPE_REMOVE,
370	node: oldChild,
371	});
372	}
373	oldHead++;	2✔
374	}
375	break;	18✔
376	}
377	if (oldHead > oldTail) {	60✔
378	while (newHead <= newTail) {	7✔
379	const newChild = this.render(	7✔
380	newElements[newHead]!,
381	scope,
382	newHead,
383	newParent,
384	newParent.part,
385	);
386	mutations.push({	7✔
387	type: MUTATION_TYPE_INSERT,
388	node: newChild,
389	afterNode: newChildren[newTail + 1],
390	});
391	newChildren[newHead] = newChild;	7✔
392	newHead++;	7✔
393	}
394	break;	7✔
395	}
396	if (oldChildren[oldHead] === undefined) {	53✔
397	oldHead++;	3✔
398	} else if (oldChildren[oldTail] === undefined) {	50✔
399	oldTail--;	1✔
400	} else if (Object.is(oldKeys[oldHead]!, newKeys[newHead]!)) {	49✔
401	const oldChild = oldChildren[oldHead]!;	22✔
402	const newChild = this.diff(	22✔
403	oldChild,
404	newElements[newHead]!,
405	scope,
406	newHead,
407	newParent,
408	);
409	if (oldChild !== newChild) {	22✔
410	mutations.push({	22✔
411	type: MUTATION_TYPE_UPDATE,
412	oldNode: oldChildren[oldHead]!,
413	newNode: newChild,
414	});
415	}
416	newChildren[newHead] = newChild;	22✔
417	oldHead++;	22✔
418	newHead++;	22✔
419	} else if (Object.is(oldKeys[oldTail]!, newKeys[newTail]!)) {	27✔
420	const oldChild = oldChildren[oldTail]!;	8✔
421	const newChild = this.diff(	8✔
422	oldChild,
423	newElements[newTail]!,
424	scope,
425	newTail,
426	newParent,
427	);
428	if (oldChild !== newChild) {	8✔
429	mutations.push({	8✔
430	type: MUTATION_TYPE_UPDATE,
431	oldNode: oldChildren[oldTail]!,
432	newNode: newChild,
433	});
434	}
435	newChildren[newTail] = newChild;	8✔
436	oldTail--;	8✔
437	newTail--;	8✔
438	} else if (	19✔
439	Object.is(oldKeys[oldHead]!, newKeys[newTail]!) &&
440	Object.is(oldKeys[oldTail]!, newKeys[newHead]!)
441	) {
442	const tailChild = this.diff(	9✔
443	oldChildren[oldTail]!,
444	newElements[newHead]!,
445	scope,
446	newHead,
447	newParent,
448	);
449	const headChild = this.diff(	9✔
450	oldChildren[oldHead]!,
451	newElements[newTail]!,
452	scope,
453	newTail,
454	newParent,
455	);
456	mutations.push({	9✔
457	type: MUTATION_TYPE_UPDATE_AND_MOVE,
458	oldNode: oldChildren[oldTail]!,
459	newNode: tailChild,
460	afterNode: oldChildren[oldHead],
461	});
462	mutations.push({	9✔
463	type: MUTATION_TYPE_UPDATE_AND_MOVE,
464	oldNode: oldChildren[oldHead]!,
465	newNode: headChild,
466	afterNode: newChildren[newTail + 1],
467	});
468	newChildren[newHead] = tailChild;	9✔
469	newChildren[newTail] = headChild;	9✔
470	oldHead++;	9✔
471	newHead++;	9✔
472	oldTail--;	9✔
473	newTail--;	9✔
474	} else {
475	newKeyToIndexMap ??= buildKeyToIndexMap(newKeys, newHead, newTail);	10✔
476
477	if (!newKeyToIndexMap.has(oldKeys[oldHead]!)) {	10✔
478	const oldChild = oldChildren[oldHead]!;	2✔
479	mutations.push({	2✔
480	type: MUTATION_TYPE_REMOVE,
481	node: oldChild,
482	});
483	oldHead++;	2✔
484	} else if (!newKeyToIndexMap.has(oldKeys[oldTail]!)) {	8✔
485	const oldChild = oldChildren[oldTail]!;	2✔
486	mutations.push({	2✔
487	type: MUTATION_TYPE_REMOVE,
488	node: oldChild,
489	});
490	oldTail--;	2✔
491	} else {
492	oldKeyToIndexMap ??= buildKeyToIndexMap(oldKeys, oldHead, oldTail);	6✔
493	const oldIndex = oldKeyToIndexMap.get(newKeys[newTail]!);	6✔
494
495	if (	6✔
496	oldIndex !== undefined &&
497	oldIndex >= oldHead &&
498	oldIndex <= oldTail &&
499	oldChildren[oldIndex] !== undefined
500	) {
501	const newChild = this.diff(	5✔
502	oldChildren[oldIndex]!,
503	newElements[newTail]!,
504	scope,
505	newTail,
506	newParent,
507	);
508	mutations.push({	5✔
509	type: MUTATION_TYPE_UPDATE_AND_MOVE,
510	oldNode: oldChildren[oldIndex]!,
511	newNode: newChild,
512	afterNode: newChildren[newTail + 1],
513	});
514	newChildren[newTail] = newChild;	5✔
515	oldChildren[oldIndex] = undefined;	5✔
516	} else {
517	const newChild = this.render(	1✔
518	newElements[newTail]!,
519	scope,
520	newTail,
521	newParent,
522	newParent.part,
523	);
524	mutations.push({	1✔
525	type: MUTATION_TYPE_INSERT,
526	node: newChild,
527	afterNode: newChildren[newTail + 1],
528	});
529	newChildren[newTail] = newChild;	1✔
530	}
531
532	newTail--;	6✔
533	}
534	}
535	}
536
537	newParent.dirty = mutations.length > 0;	25✔
538	}
539
540	private async _flush(): Promise<void> {
541	while (true) {	250✔
542	let update: Update \| undefined;
543
544	this._flushLanes \|= this._stagedLanes;	503✔
545	this._stagedLanes = NoLanes;	503✔
546
547	while ((update = this._updateQueue.peek()) !== undefined) {	503✔
548	if ((this._flushLanes & update.lanes) !== update.lanes) {	257✔
549	break;	1✔
550	}
551	this._updateBatch.push(this._updateQueue.dequeue()!);	256✔
552	}
553
554	if (this._updateBatch.length === 0) {	503✔
555	break;	250✔
556	}
557
558	try {	253✔
559	const commitBatch: Commit[] = [];	253✔
560	const flushSync = (this._flushLanes & SyncLane) === SyncLane;	253✔
561
562	for (const update of this._updateBatch) {	253✔
563	const { lanes, unit } = update;	256✔
564
565	if ((unit.pendingLanes & lanes) === NoLanes) {	256✔
566	continue;	2✔
567	}
568
569	if (!flushSync && commitBatch.length > 0) {	254✔
570	await this._adapter.yieldToMain();	1✔
571	}
572
573	commitBatch.push(unit.prepare(this._flushLanes, this));	254✔
574	}
575
576	if (commitBatch.length > 0) {	238✔
577	const commit = () => {	238✔
578	for (const commit of commitBatch) {	238✔
579	commit();	239✔
580	}
581	};
582	if (flushSync) {	238✔
583	commit();	24✔
584	} else if (this._flushLanes & ViewTransitionLane) {	214✔
585	await this._adapter.startViewTransition(commit);	1✔
586	} else {
587	await this._adapter.requestCommit(commit);	213✔
588	}
589	}
590
591	for (const { controller } of this._updateBatch) {	236✔
592	controller.resolve();	239✔
593	}
594	} catch (error) {
595	for (const { controller } of this._updateBatch) {	17✔
596	controller.reject(error);	17✔
597	}
598	} finally {
599	this._updateBatch = [];	253✔
600	}
601	}
602
603	this._flushLanes = NoLanes;	250✔
604	}
605	}
606
607	export async function waitForStep(runtime: Runtime): Promise<boolean> {
608	if (runtime._updateBatch.length > 0) {	40✔
609	for (const update of runtime._updateBatch) {	3✔
610	await update.controller.promise;	3✔
611	}
612	return true;	3✔
613	} else {
614	const update = runtime._updateQueue.peek();	37✔
615	if (update !== undefined) {	37✔
616	await update.controller.promise;	34✔
617	return true;	34✔
618	}
619	return false;	3✔
620	}
621	}
622
623	function buildKeyToIndexMap<T>(
624	keys: T[],
625	head: number,
626	tail: number,
627	): Map<T, number> {
628	const keyToIndexMap = new Map();	14✔
629	for (let i = head; i <= tail; i++) {	14✔
630	keyToIndexMap.set(keys[i]!, i);	48✔
631	}
632	return keyToIndexMap;	14✔
633	}
634
635	function compareUpdates(update1: Update, update2: Update): number {
636	const lane1 = getHighestPriorityLane(update1.lanes);	4✔
637	const lane2 = getHighestPriorityLane(update2.lanes);	4✔
638	const level1 = update1.unit.level;	4✔
639	const level2 = update2.unit.level;	4✔
640	return lane1 !== lane2 ? lane1 - lane2 : level1 - level2;	4✔
641	}

emonkak / barebind / 27772560676

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