Tom Boullay
51 lines
1.1 KiB
TypeScript
51 lines
1.1 KiB
TypeScript
type SizeSnapshot = {
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width: number;
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height: number;
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pixelRatio: number;
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};
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type SizeListener = (snapshot: SizeSnapshot) => void;
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export class Sizes {
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private snapshot: SizeSnapshot;
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private readonly listeners = new Set<SizeListener>();
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private readonly handleResize = (): void => {
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this.snapshot = Sizes.readWindow();
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this.emit();
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};
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constructor() {
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this.snapshot = Sizes.readWindow();
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window.addEventListener("resize", this.handleResize);
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}
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subscribe(listener: SizeListener): () => void {
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this.listeners.add(listener);
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return () => {
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this.listeners.delete(listener);
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};
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}
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getSnapshot(): SizeSnapshot {
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return this.snapshot;
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}
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destroy(): void {
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window.removeEventListener("resize", this.handleResize);
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this.listeners.clear();
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}
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private emit(): void {
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this.listeners.forEach((listener) => listener(this.snapshot));
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}
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private static readWindow(): SizeSnapshot {
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return {
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width: window.innerWidth,
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height: window.innerHeight,
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pixelRatio: Math.min(window.devicePixelRatio, 2),
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};
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}
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}
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