text: 'use strict'
  
  const LRU = require('lru-cache')
  
  const MAX_SIZE = 50 * 1024 * 1024 // 50MB
  const MAX_AGE = 3 * 60 * 1000
  
  let MEMOIZED = new LRU({
    max: MAX_SIZE,
    maxAge: MAX_AGE,
    length: (entry, key) => {
      if (key.startsWith('key:')) {
        return entry.data.length
      } else if (key.startsWith('digest:')) {
        return entry.length
      }
    }
  })
  
  module.exports.clearMemoized = clearMemoized
  function clearMemoized () {
    const old = {}
    MEMOIZED.forEach((v, k) => {
      old[k] = v
    })
    MEMOIZED.reset()
    return old
  }
  
  module.exports.put = put
  function put (cache, entry, data, opts) {
    pickMem(opts).set(`key:${cache}:${entry.key}`, { entry, data })
    putDigest(cache, entry.integrity, data, opts)
  }
  
  module.exports.put.byDigest = putDigest
  function putDigest (cache, integrity, data, opts) {
    pickMem(opts).set(`digest:${cache}:${integrity}`, data)
  }
  
  module.exports.get = get
  function get (cache, key, opts) {
    return pickMem(opts).get(`key:${cache}:${key}`)
  }
  
  module.exports.get.byDigest = getDigest
  function getDigest (cache, integrity, opts) {
    return pickMem(opts).get(`digest:${cache}:${integrity}`)
  }
  
  class ObjProxy {
    constructor (obj) {
      this.obj = obj
    }
    get (key) { return this.obj[key] }
    set (key, val) { this.obj[key] = val }
  }
  
  function pickMem (opts) {
    if (!opts || !opts.memoize) {
      return MEMOIZED
    } else if (opts.memoize.get && opts.memoize.set) {
      return opts.memoize
    } else if (typeof opts.memoize === 'object') {
      return new ObjProxy(opts.memoize)
    } else {
      return MEMOIZED
    }
  }
  