cleanup comments

Author: mLuby

.gitignore

@@ -0,0 +1 @@
+.DS_Store

lib/spec.js

@@ -322,129 +322,3 @@ describe('Recommendation Engine', function () {
     it('applies deltas rather than recalculating all recommendations when a rating changes')
   })
 })
-
-/*
-xdescribe('bubbleSort', function() {
-  var array1 = [0,-1,1,5,-5,2,3,7];
-  var copyOfArray1 = [0,-1,1,5,-5,2,3,7];
-  var sortedArray1 = [-5,-1,0,1,2,3,5,7];
-
-  it('should sort an array of integers', function() {
-    bubbleSort(array1).forEach(function(element, index){
-      expect(element).to.be(sortedArray1[index]);
-    });
-  });
-  it('should not mutate the original array', function() {
-    bubbleSort(array1);
-    array1.forEach(function(element, index){
-      expect(element).to.be(copyOfArray1[index]);
-    });
-  });
-});
-
-xdescribe('mergeSort', function() {
-  var array1 = [0,-1,1,5,-5,2,3,7];
-  var copyOfArray1 = [0,-1,1,5,-5,2,3,7];
-  var sortedArray1 = [-5,-1,0,1,2,3,5,7];
-
-  it('should sort an array of integers', function() {
-    mergeSort(array1).forEach(function(element, index){
-      expect(element).to.be(sortedArray1[index]);
-    });
-  });
-  it('should not mutate the original array', function() {
-    mergeSort(array1);
-    array1.forEach(function(element, index){
-      expect(element).to.be(copyOfArray1[index]);
-    });
-  });
-  it('should sort a large array faster than bubbleSort', function(){
-    var array = [];
-    for(var i=0; i<1e3; i++) {
-      array.push(Math.floor(Math.random() * 100));
-    }
-    var bubbleSortResults = timer(bubbleSort, array);
-    var mergeSortResults = timer(mergeSort, array);
-    mergeSortResults.result.forEach(function(element, index){
-      expect(element).to.be(bubbleSortResults.result[index]);
-    });
-    expect(mergeSortResults.timeElapsed).to.be.below(bubbleSortResults.timeElapsed);
-  });
-});
-*/
-// describe('quickSort', function() {
-//   var array, sortedArray;
-//   beforeEach(function(){
-//     array = [1234, 4521, 2252, 5103, 10001, 21, 235];
-//     sortedArray = [21, 235, 1234, 2252, 4521, 5103, 10001];
-//   });
-//
-//   it('should sort an array of integers', function() {
-//     expect(quickSort(array)).to.deep.equal(sortedArray);
-//   });
-//
-//   it('works for negative numbers', function(){
-//     array.push(-3);
-//     sortedArray.unshift(-3);
-//     expect(quickSort(array)).to.deep.equal(sortedArray);
-//   })
-//
-//   it('works for decimals', function(){
-//     array.push(7.8);
-//     sortedArray.unshift(7.8);
-//     expect(quickSort(array)).to.deep.equal(sortedArray);
-//   })
-// });
-//
-// describe('radixSort', function() {
-//   var array, sortedArray;
-//   beforeEach(function(){
-//     array = [1234, 4521, 2252, 5103, 10001, 21, 235];
-//     sortedArray = [21, 235, 1234, 2252, 4521, 5103, 10001];
-//   });
-//
-//   it('should sort an array of integers', function() {
-//     expect(radixSort(array)).to.deep.equal(sortedArray);
-//   });
-//
-//   xit('works for characters', function(){
-//     var array = ['bob', 'alice', 'carl', 'thx1138'] ;
-//     var sortedArray = ['alice', 'bob', 'carl', 'thx1138'] ;
-//     expect(radixSort(array)).to.deep.equal(sortedArray);
-//   })
-//
-//   xit('works for decimals', function(){
-//     array.push(7.8);
-//     sortedArray.unshift(7.8);
-//     expect(radixSort(array)).to.deep.equal(sortedArray);
-//   })
-//
-//   xit('works for negative numbers', function(){
-//     array.push(-3);
-//     sortedArray.unshift(-3);
-//     expect(radixSort(array)).to.deep.equal(sortedArray);
-//   })
-// });
-
-/*
-xdescribe('Extra Credit', function() {
-  it('sort non-integer arrays');
-  it('write tests to compare sorting speeds for large arrays');
-  it('write tests for sorting stability');
-  it('implement selectionSort');
-  it('implement insertionSort');
-});
-*/
-
-// function timer(sortingAlgorithm, array){
-//   // copy array;
-//   var tempArray = array.slice();
-//   // time the algorithm
-//   var start = new Date().getTime();
-//   var result = sortingAlgorithm(tempArray);
-//   var end = new Date().getTime();
-//   return {
-//     timeElapsed : end - start,
-//     result      : result
-//   };
-// };

src/recommendationEngine.js

@@ -1,6 +1,9 @@
-Array.prototype.contains = function (primitive) {
-  return this.indexOf(primitive) !== -1 // <- Nobody wants to read that!
-}
+Object.defineProperty(Array.prototype, 'contains', {
+  value: function (primitive) {
+    return this.indexOf(primitive) !== -1 // <- Nobody wants to read that!
+  },
+  enumerable: false // Looking at object's keys will NOT include this property.
+});
 
 function u (list1, list2) {
   return list1.concat(list2).reduce(function(union, item){
@@ -69,7 +72,6 @@ function predictLike (itemId, user, users) {
 }
 
 function recommendationsFor(user, users) {
-  // calculate all items for
   var allItemIds = users.reduce(getItemIds, [])
   function getItemIds (itemIds, user) {
     return user.likes.concat(user.dislikes).reduce(aggregateUnique, itemIds)