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55 lines
1.0 KiB
JavaScript
55 lines
1.0 KiB
JavaScript
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// Used for Category.asyncFindByIds
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//
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// It's a cache that handles multiple lookups at a time.
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export class MultiCache {
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constructor(cb) {
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this.cb = cb;
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this.values = new Map();
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this.fetchTimes = [];
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}
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reset() {
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this.values = new Map();
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this.fetchTimes = [];
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}
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hadTooManyCalls() {
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const [t1, t2] = this.fetchTimes;
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return t1 && t2 && t2 - t1 < 1000;
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}
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async fetch(ids) {
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this.fetchTimes = [this.fetchTimes[this.fetchTimes.length - 1], new Date()];
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const notFound = [];
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for (const id of ids) {
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if (!this.values.has(id)) {
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notFound.push(id);
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}
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}
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if (notFound.length !== 0) {
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const request = this.cb(notFound);
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for (const id of notFound) {
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this.values.set(id, request);
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}
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request.catch(() => {
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for (const id of notFound) {
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this.values.delete(id);
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}
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});
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}
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const response = new Map();
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for (const id of ids) {
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response.set(id, (await this.values.get(id)).get(id));
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}
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return response;
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}
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}
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