closure based caching

gistfile1.js

'use strict'

function Obj() {}

Obj.prototype.getVal = getVal
Obj.prototype.clearCache = function clearCachedVal() {
  console.log('clearing the cache')
  this.getVal = getVal
}

function getVal(x) {
  var _val
  console.log('setting cached data')
  this.getVal = function getCachedVal() {
    console.log('serving cached data')
    return _val
  }
  //do stuff with _val
  _val = x
  return _val
}

var obj = new Obj()

console.log(obj.getVal(1))
console.log(obj.getVal(2))
obj.clearCache()
console.log(obj.getVal(2))