JavaScript Masterclass Homework

01_functional_vs_OO.js

// Exercise 1 - OO || !OO
// Define a data structure for cars (make and color), and a function
// that logs a string like "I'm a red Mercedes" to the console.
// Make two versions: a functional version, and a object-oriented version.

var logCar = function(car) {
    console.log("I'm a " + car.color + ' ' + car.make);
}

logCar({ color: 'blue', make: 'BMW' });

var Car = function(make, color) {
    this.log = function() {
        console.log("I'm a " + color + ' ' + make);
    }
}

new Car('Ferrari', 'red').log();

07_caching_wrapper.js

// 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)
Function.prototype.cached = function() {
    var cache = { }
    var method = this;
    return function(input) {
        var cached = cache[input];
        if ( cached == null ) {
            cached = method(input);
            cache[input] = cached;
        }
        return cached;
    }
}

Math.sin = Math.sin.cached();
console.log(Math.sin(1));
console.log(Math.sin(1));


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

isPrime = isPrime.cached();
console.log(isPrime(2147483647));
console.log(isPrime(2147483647));