misskey/src/misc/cache.ts

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export class Cache<T> {
private cache: Map<string | null, { date: number; value: T; }>;
private lifetime: number;
constructor(lifetime: Cache<never>['lifetime']) {
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this.cache = new Map();
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this.lifetime = lifetime;
}
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public set(key: string | null, value: T): void {
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this.cache.set(key, {
date: Date.now(),
value
});
}
public get(key: string | null): T | null {
const cached = this.cache.get(key);
if (cached == null) return null;
if ((Date.now() - cached.date) > this.lifetime) {
this.cache.delete(key);
return null;
}
return cached.value;
}
}