Add reaction to feed

reactions.service.ts

import Redis from 'ioredis';

export class ReactionService {
  private redisClient: Redis

  constructor() {
    // connect to your redis instance first
    this.redisClient = new Redis()
  }

  async addReactionToFeed(
    userID: string,
    { type, feedID }: ReactionInput
  ) {
    const key = `${feedID}:${type}`
    
    await this.redisClient.sadd(key, userID)
    return { success: true }
  }

  async removeReactionFromFeed(
    userID: string,
    { type, feedID }: ReactionInput
  ) {
    const key = `${feedID}:${type}`

    // this check is not really important as redis will handle the case
    // where the item is not in the set
    const isMember = await this.redisClient.sismember(key, userID)
    if (isMember) {
      await this.redisClient.srem(key, userID)
    }

    return { success: true }
  }

  async getFeedReactions(feedID: string) {
    // Reactions is an enum
    const [DEAD, STRENGTH, HEART, LIKE] = await Promise.all([
      this.redisClient.scard(`${feedID}:${Reactions.DEAD}`),
      this.redisClient.scard(`${feedID}:${Reactions.STRENGTH}`),
      this.redisClient.scard(`${feedID}:${Reactions.HEART}`),
      this.redisClient.scard(`${feedID}:${Reactions.LIKE}`),
    ])
    
    return {
      DEAD, STRENGTH, HEART, LIKE
    }
  }
  
  async removeReactionsForFeed(feedID: string) {
    // this is used when the feed item is deleted
    await Promise.all([
      this.redisClient.del(`${feedID}:${Reactions.DEAD}`),
      this.redisClient.del(`${feedID}:${Reactions.STRENGTH}`),
      this.redisClient.del(`${feedID}:${Reactions.HEART}`),
      this.redisClient.del(`${feedID}:${Reactions.LIKE}`),
    ])
    
    return { success: true }
  }
}