Redis Cache Lib

cache.ts

import * as Redis from 'redis';
import * as superjson from 'superjson';

export class Cache {
  private static client: Redis.RedisClient;
  private static readonly prefix = process.env.CACHE_PREFIX || '';
  private static readonly bypassCache = process.env.CACHE_BYPASS === 'true';

  static async get<T>(key: (string | number | Date)[], getValue: () => Promise<T>): Promise<T> {
    if (this.bypassCache) {
      return getValue();
    }
    if (!this.client || !this.client.isReady) {
      await this.initializeClient();
    }
    const cacheKey = this.buildCacheKey(key);
    const value = await this.client.get(cacheKey);
    if (value) {
      return superjson.parse<T>(value);
    } else {
      const newValue = await getValue();
      await this.update(key, newValue);
      return newValue;
    }
  }

  static async update(key: (string | number | Date)[], value: any) {
    if (this.bypassCache) {
      return;
    }
    if (!this.client || !this.client.isReady) {
      await this.initializeClient();
    }
    const cacheKey = this.buildCacheKey(key);
    const serializedValue = superjson.stringify(value);
    await this.client.set(cacheKey, serializedValue);
    await this.client.expire(cacheKey, Number(process.env.CACHE_TTL));
  }

  static async invalidate(key: (string | number | Date)[]) {
    if (this.bypassCache) {
      return;
    }
    if (!this.client || !this.client.isReady) {
      await this.initializeClient();
    }
    const cacheKey = this.buildCacheKey(key);
    const keys = await this.client.keys(`${cacheKey}*`);
    if (keys.length > 0) {
      await this.client.del(keys);
    }
  }

  static async clear() {
    if (this.bypassCache) {
      return;
    }
    if (!this.client || !this.client.isReady) {
      await this.initializeClient();
    }
    await this.invalidate([]);
  }

  private static async initializeClient() {
    this.client = await Redis.createClient({ url: process.env.REDIS_URL });
    await this.client.connect();
  }
  
  static async dispose(){
    await this.client?.disconnect();
  }

  private static buildCacheKey(key: (string | number | Date)[]) {
    return [this.prefix, ...key].map(element => {
      if (element instanceof Date) {
        return element.getTime();
      }
      return element;
    }).join('_');
  }
}