@ariva-mds/mds/lib/esm/lrucache.js

Stock market data

export class LruCache {
    constructor(provider, maxEntries) {
        this.values = new Map();
        this.maxEntries = 200;
        this.maxEntries = maxEntries;
        this.provider = provider;
    }
    get(arg0) {
        const cacheKey = JSON.stringify(arg0);
        const hasKey = this.values.has(cacheKey);
        if (hasKey) {
            // peek the entry, re-insert for LRU strategy
            const entry = this.values.get(cacheKey);
            this.values.delete(cacheKey);
            if (entry != undefined) {
                this.values.set(cacheKey, entry);
                return new Promise((resolve, reject) => {
                    if (entry != undefined) {
                        resolve(entry);
                    }
                    else {
                        reject("not found");
                    }
                });
            }
            else {
                return new Promise((resolve, reject) => {
                    reject("some error while looking up");
                });
            }
        }
        else {
            return this.provider(arg0).then(resolved => {
                this.put(cacheKey, resolved);
                return resolved;
            });
        }
    }
    put(key, value) {
        if (this.values.size >= this.maxEntries) {
            // least-recently used cache eviction strategy
            const keyToDelete = this.values.keys().next().value;
            this.values.delete(keyToDelete);
        }
        this.values.set(key, value);
    }
}