Functional Programming Exercise

gistfile1.js

//Copy this over the contents at tddbin.com
//Replace the [] in the assert statements with a functional equivalant
//Reference here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array
//Lambda syntax: (x,y) => x + y, works in firefox, try it out :)

function range(start, end, jump) {
	jump = jump || 1
	if (start && !end)
	return actualRange(0, start, jump)
	return actualRange(start, end, jump)
}

function actualRange(start, end, jump) {
	var result = []
	for (var i = start; i < end; i += jump)
		result.push(i)
	return result
}

describe('For loops vs Map/Filter/Reduce', function() {

		it('creates the same list', function() {
				var numbers = [];
				for (var i = 0; i < 100; i++){
				numbers.push(i * 2)
				}
				assert.deepEqual(numbers, []); 
				});

		it('creates the same list', function() {
				var people = ['james', 'jane', 'anne'];
				var peopleStartingWithJ = [];
				for (var i = 0; i < people.length; i++) {
				if (people[i][0] === 'j')
				peopleStartingWithJ.push(people[i])
				}
				assert.deepEqual(peopleStartingWithJ, [])
				});

		it('creates the same list', function() {
				var people = ['james', 'jane', 'anne'];
				var firstLetterOfName = [];
				for (var i = 0; i < people.length; i++) {
				firstLetterOfName.push(people[i][0])
				}
				assert.deepEqual(firstLetterOfName, [])
				});

		it('creates the same list', function() {
				var people = [5, 10, 15]
				var sum = 0
				for (var i = 0; i < people.length; i++) {
				sum += people[i]
				}
				assert.equal(sum, 0)
				});

		it('creates the same list', function() {
				var people = [11, 10, 15]
				var allLargerThan10 = true;
				for (var i = 0; i < people.length; i++) {
				if (people[i] <= 10) {
				allLargerThan10 = false;
				break;
				}
				}
				assert.deepEqual(allLargerThan10, true)
				});

		it('creates the same list', function() {
				var people = [5, 10, 15]
				var anyLargerThan10 = false;
				for (var i = 0; i < people.length; i++) {
				if (people[i] > 10) {
				anyLargerThan10 = true;
				break;
				}
				}
				assert.deepEqual(anyLargerThan10, false)
				});

		//Reduce Challenges
		//Note: I'm not encouraging using reduce everywhere, this is just an exercise
		it('solves this using reduce', function() {
				var people = ['james', 'jane', 'anne'];
				var firstLetterOfName = [];
				for (var i = 0; i < people.length; i++) {
				firstLetterOfName.push(people[i][0])
				}
				assert.deepEqual(firstLetterOfName, [])
				});

		it('solves this using reduce', function() {
				var people = ['james', 'jane', 'anne'];
				var peopleStartingWithJ = [];
				for (var i = 0; i < people.length; i++) {
				if (people[i][0] === 'j')
				peopleStartingWithJ.push(people[i])
				}
				assert.deepEqual(peopleStartingWithJ, [])
				});

		//Nesting
		it('returns the indicies of two product prices that add up to credit', function() {
				var credit = 100;
				var productPrices = [5, 75, 25]
				var productIndicies = [0,0];
				for (var i = 0; i < productPrices.length; i++)
				for (var j = i + 1; j < productPrices.length; j++)
				if (productPrices[i] + productPrices[j] === credit) productIndicies = [i,j]

				assert.deepEqual(productIndicies, [])
				});

});