48 lines
962 B
TypeScript
48 lines
962 B
TypeScript
import { ExcalidrawElement } from "../element/types";
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export interface SceneStateCallback {
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(): void;
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}
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export interface SceneStateCallbackRemover {
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(): void;
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}
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class SceneState {
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private callbacks: Set<SceneStateCallback> = new Set();
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constructor(private _elements: readonly ExcalidrawElement[] = []) {}
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getAllElements() {
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return this._elements;
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}
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replaceAllElements(nextElements: readonly ExcalidrawElement[]) {
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this._elements = nextElements;
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this.informMutation();
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}
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informMutation() {
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for (const callback of Array.from(this.callbacks)) {
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callback();
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}
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}
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addCallback(cb: SceneStateCallback): SceneStateCallbackRemover {
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if (this.callbacks.has(cb)) {
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throw new Error();
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}
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this.callbacks.add(cb);
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return () => {
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if (!this.callbacks.has(cb)) {
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throw new Error();
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}
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this.callbacks.delete(cb);
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};
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}
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}
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export const globalSceneState = new SceneState();
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