Implementing Caching Strategies in NestJS

Caching allows you to store the results of expensive operations and reuse them for subsequent requests, reducing the load on your API and improving response times. Let's understand on how we can implement caching strategies in NestJS to improve API performance.

Installing a Caching Provider

NestJS supports various caching providers, such as Redis, Memcached, and in-memory caching. For this example, we'll use the cache-manager package for in-memory caching. Install it using:

npm install cache-manager        

Configuring Caching in NestJS

First, create a caching module to encapsulate the caching logic. Create a new file cache.module.ts:

import { Module } from '@nestjs/common';
import { CacheManager } from './cache.manager';

@Module({
  providers: [CacheManager],
  exports: [CacheManager],
})

export class CacheModule {}        

Next, create a caching manager class cache.manager.ts:

import * as cacheManager from 'cache-manager';

export class CacheManager {
  private cache;
  constructor() {
    this.cache = cacheManager.caching({
      store: 'memory',
      ttl: 300, // 5 minutes
    });
  }

  async get(key: string) {
    return this.cache.get(key);
  }

  async set(key: string, value: any) {
    return this.cache.set(key, value);
  }

  async del(key: string) {
    return this.cache.del(key);
  }
}        

Using Caching in Your Application

You can now use the caching manager in your services to cache expensive operations. For example, in a service method:

import { Injectable } from '@nestjs/common';
import { CacheManager } from './cache.manager';

@Injectable()
export class MyService {
  constructor(private readonly cacheManager: CacheManager) {}

  async getExpensiveData(key: string) {
    let data = await this.cacheManager.get(key);
    if (!data) {
      data = await this.fetchDataFromDatabase();
      await this.cacheManager.set(key, data);
    }
    return data;
  }

  private async fetchDataFromDatabase() {
    return { message: 'This is the data' };
  }
}        

Implementing caching strategies in NestJS can significantly improve API performance by reducing the load on your API and improving response times. In this article, we explored how to configure and use in-memory caching in a NestJS application.