JSMasterclass - Homeworks

var cachy = (function() {
  var cache = {}
  var executor = function(func, args) {
    var funcIdentifier = func.toString(),
        argsIdentifier = args.join(", ")
    
    if(cache.hasOwnProperty(funcIdentifier) && cache[func.toString()].hasOwnProperty(argsIdentifier)) {
      console.log("cached baby!")
      return cache[funcIdentifier][argsIdentifier]
    } else {
      console.log("not cached yet!")
      cache[funcIdentifier] = cache[funcIdentifier] || {}
      return cache[funcIdentifier][argsIdentifier] = func.call(null, args)
    }
  }
  return executor
})()

var sin = function(arg) {
  return Math.sin(arg)
}

console.log(cachy(sin, [2]))
console.log(cachy(sin, [2]))


// Part 1.
// Implement a function prototype extension that caches function results for
// the same input arguments of a function with one parameter.
//
// For example:
// Make sin(1) have the result of Math.sin(1), but use a cached value
// for future calls.
//
// Part 2.
// Use this new function to refactor the code example.
// Some good test numbers: 524287, 9369319, 2147483647 (all primes)

var isPrime = function ( num ) { 
  var prime = num != 1;
  for ( var i = 2; i < num; i++ ) { 
    if ( num % i == 0 ) { 
      prime = false; 
      break; 
    } 
  }
  return prime; 
} 

console.log(cachy(isPrime, [2]))
console.log(cachy(isPrime, [2]))
console.log(cachy(isPrime, [4]))
console.log(cachy(isPrime, [1]))
console.log(cachy(isPrime, [4]))