Functional programming snippets

findlongestword.js

// Non functional programming way

function findLongestWord(arr) {
   var max = Number.NEGATIVE_INFINITY;
   for (var i = 0; i < arr.length; i++) {
      if (arr[i].length > max) {
         max = arr[i].length;
      }
   }

   return max;
}

var arr = ['a', 'bbb', 'hellociao'];

findLongestWord(arr);


// Functional programming way

function getLength(word) {
   return word.length;
}

function findMax(a, b) {
   return Math.max(a, b);
}

function findLongestWord(arr) {
   return arr
      .map(getLength)
      .reduce(findMax);
}

var arr = ['a', 'bbb', 'hellociao'];

findLongestWord(arr);

map.js

// Create an increase(anArray, byNumber) function, that increases all the numbers in an array, by a given number.

// Non functional programming way
var sourceArray = [1, 2, 3];

function increase(anArray, byNumber) {
	for(var i=0; i<anArray.length; i++) {
		anArray[i] += byNumber;
	}
}

increase(sourceArray, 2);

console.log(sourceArray); // ??

// Functional programming way
var sourceArray = [1, 2, 3];

function increaseFP(anArray, byNumber) {
	return anArray.map(function (number) {
		return number + byNumber;
	});
}

var newArray = increaseFP(sourceArray, 2);

console.log(increaseFP(sourceArray, 2)); // ??
console.log(sourceArray); // ??


// Functional programming way (ES6)
var sourceArray = [1, 2, 3];

function increaseFP(anArray, byNumber) {
	return anArray.map(number => number + byNumber);
}

console.log(increaseFP(sourceArray, 2)); // ??
console.log(sourceArray); // ??