Merge pull request #88 from joshuacurl/map

Map for data structures

data_structures/hash_table.js

@@ -102,4 +102,18 @@ HashTable.prototype._increaseCapacity = function () {
   }
 };
 
+HashTable.prototype.forEach = function (fn) {
+  var applyFunction = function (linkedList) {
+    linkedList.forEach(function (elem) {
+      fn(elem.k);
+    });
+  };
+
+  for (var i = 0; i < this._table.length; i++) {
+    if (this._table[i]) {
+      applyFunction(this._table[i]);
+    }
+  }
+};
+
 module.exports = HashTable;

data_structures/heap.js

@@ -89,6 +89,18 @@ MinHeap.prototype.heapify = function (a) {
   }
 };
 
+MinHeap.prototype.forEach = function (fn) {
+  var elementsCopy = JSON.parse(JSON.stringify(this._elements));
+
+  var element = this.extract();
+  while (typeof element !== 'undefined') {
+    fn(element);
+    element = this.extract();
+  }
+
+  this._elements = elementsCopy;
+};
+
 /**
  * Max Heap, keeps the highest element always on top
  *

data_structures/queue.js

@@ -46,4 +46,8 @@ Queue.prototype.peek = function () {
   return this._elements.get(0);
 };
 
+Queue.prototype.forEach = function (fn) {
+  this._elements.forEach(fn);
+};
+
 module.exports = Queue;

data_structures/set.js

@@ -36,4 +36,8 @@ HashSet.prototype.contains = function (e) {
   return this._elements.get(e) !== undefined;
 };
 
+HashSet.prototype.forEach = function (fn) {
+  this._elements.forEach(fn);
+};
+
 module.exports = HashSet;

test/data_structures/hash_table.js

@@ -123,5 +123,19 @@ describe('Hash Table', function () {
     h.put(o, 'foo');
     assert.equal(h.get(o), 'foo');
   });
+
+  it('should perform a function to all keys with forEach', function () {
+    var h = new HashTable();
+    h.put(1, true);
+    h.put(2, true);
+    h.put(3, true);
+
+    var total = 0;
+    h.forEach(function (elem) {
+      total += elem;
+    });
+
+    assert.equal(total, 6);
+  });
 });
 

test/data_structures/heap.js

@@ -53,6 +53,19 @@ describe('Min Heap', function () {
 
     assert(h.isEmpty());
   });
+
+  it('should perform a function to all elements from smallest to largest' +
+     ' with forEach', function () {
+    var h = new heap.MinHeap();
+    h.heapify([3, 10, 1000, 0, 2, 1]);
+
+    var output = [];
+    h.forEach(function (n) {
+      output.push(n);
+    });
+
+    assert.deepEqual(output, [0, 1, 2, 3, 10, 1000]);
+  });
 });
 
 describe('Max Heap', function () {
@@ -105,4 +118,17 @@ describe('Max Heap', function () {
 
     assert(h.isEmpty());
   });
+
+  it('should perform a function to all elements from largest to smallest' +
+     ' with forEach', function () {
+    var h = new heap.MaxHeap();
+    h.heapify([3, 10, 1000, 0, 2, 1]);
+
+    var output = [];
+    h.forEach(function (n) {
+      output.push(n);
+    });
+
+    assert.deepEqual(output, [1000, 10, 3, 2, 1, 0]);
+  });
 });

test/data_structures/queue.js

@@ -35,6 +35,20 @@ describe('Queue', function () {
       q.pop();
       assert.equal(q.peek(), 2);
     });
+
+  it('should perform a function to all elements with forEach', function () {
+    var q = new Queue();
+    q.push(1);
+    q.push(2);
+    q.push(3);
+
+    var total = 0;
+    q.forEach(function (elem) {
+      total += elem;
+    });
+
+    assert.equal(total, 6);
+  });
 });
 
 

test/data_structures/set.js

@@ -57,6 +57,18 @@ describe('HashSet', function () {
     assert(s.contains(1));
     assert(!s.contains(4));
   });
+
+  it('should perform a function to all elements with forEach', function () {
+    var s = new HashSet();
+    s.add(1, 2, 3);
+
+    var total = 0;
+    s.forEach(function (elem) {
+      total += elem;
+    });
+
+    assert.equal(total, 6);
+  });
 });