@iin-mdc/koa-utils/lib/cache-store.js

"use strict"

const LRU = require("lru-cache")

const LRU_SIZE = 5000

class CacheStore {
  constructor(fetchFn) {
    this.fetchFn = fetchFn
    this.store = new LRU(LRU_SIZE)
  }

  async fetch(key) {
    if (!key) {
      return null
    }

    if (this.store.has(key)) {
      return this.store.get(key)
    }

    let res = null
    try {
      res = await this.fetchFn(key)
      this.store.set(key, res)
    } catch (e) {} // eslint-disable-line no-empty

    return res
  }

  set(key, value) {
    return this.store.set(key, value)
  }
}

module.exports = CacheStore