lru-cache-ext/lib/index.js

Thin wrapper around lru-cache with extended functionality.

import assert from 'assert';
import { LRUCache as LRU } from 'lru-cache';

export default class LRUe extends LRU {
  constructor({ cacheNull = true, ...options }) {
    super(options);
    assert(!('maxAge' in options), 'Please use "ttl" instead of "maxAge"');
    assert('max' in options, 'Please add a "max" value');
    this.cacheNull = cacheNull;
  }

  async memoize(key, valueFn, ...args) {
    assert(typeof valueFn === 'function');
    if (!this.has(key)) {
      this.set(key, valueFn(...args));
    }
    try {
      const r = await this.peek(key);
      if (r === null && this.cacheNull !== true) {
        this.delete(key);
      }
      return r;
    } catch (error) {
      this.delete(key);
      throw error;
    }
  }

  memoizeSync(key, valueFn, ...args) {
    assert(typeof valueFn === 'function');
    if (!this.has(key)) {
      const r = valueFn(...args);
      assert(!(r instanceof Promise), 'Use memoize() instead');
      this.set(key, r);
    }
    const r = this.peek(key);
    if (r === null && this.cacheNull !== true) {
      this.delete(key);
    }
    return r;
  }
}