All, None & Any - Functional Programming

All, None & Any - Functional Programming

1/10/2016

Description:

As a part of this Kata, you need to create three functions that one needs to be able to call upon an array:

1.all

This function returns true only if the predicate supplied returns true for all the items in the array

[1, 2, 3].all(isGreaterThanZero) => true
[-1, 0, 2].all(isGreaterThanZero) => false

2.none

This function returns true only if the predicate supplied returns false for all the items in the array

[-1, 2, 3].none(isLessThanZero) => false
[-1, -2, -3].none(isGreaterThanZero) => true

3.any

This function returns true if at least one of the items in the array returns true for the predicate supplied

[-1, 2, 3].any(isGreaterThanZero) => true
[-1, -2, -3].any(isGreaterThanZero) => false

// p is the callbacks function here.
// function isGreaterThanZero(num) {
  return num > 0
}

My Solution:

Array.prototype.all = function (p) {
  for (var i=0; i<this.length; i++) {
    if (!p(this[i]))
      return false;
  }
  return true;
};

Array.prototype.none = function (p) {
  for (var i=0; i<this.length; i++) {
    if (p(this[i]))
      return false;
  }
  return true;
};

Array.prototype.any = function (p) {
  for (var i=0; i<this.length; i++) {
    if (p(this[i]))
      return true;
  }
  return false;
};