Added a set of extra credit array-related tasks that require the user to reimplemen…

app/arraysExtraCredit.js

@@ -0,0 +1,29 @@
+exports = (typeof window === 'undefined') ? global : window;
+
+/*Pay special attention to what each function is supposed to return
+as well as what the .length property of each array should be*/
+exports.arraysExtraCreditAnswers = {
+
+  indexOf : function(arr, item) {
+
+  },
+
+  push : function(arr,item) {
+
+  },
+
+  pop : function(arr) {
+
+  },
+
+  unshift : function(arr,item) {
+
+  },
+
+  shift : function(arr) {
+
+  },
+
+  concat : function(arr1, arr2) {
+
+}

tests/app/arraysExtraCredit.js

@@ -0,0 +1,72 @@
+if ( typeof window === 'undefined' ) {
+  require('../../app/arraysExraCredit');
+  var expect = require('chai').expect;
+}
+
+xdescribe('arraysExtraCredit', function() {
+  var a;
+
+  /*create an array-like object (subclass of Array) that is missing the methods that
+  the user needs to implement */
+  var ArrayLike = function() {
+    Array.call(this);
+  }
+  ArrayLike.prototype = Object.create(Array.prototype);
+  ArrayLike.prototype.indexOf = undefined;
+  ArrayLike.prototype.push = undefined;
+  ArrayLike.prototype.pop = undefined;
+  ArrayLike.prototype.unshift = undefined;
+  ArrayLike.prototype.shift = undefined;
+  ArrayLike.prototype.concat = undefined;
+
+  beforeEach(function() {
+    a = new ArrayLike();
+    a = [ 1, 2, 3, 4 ];
+  });
+
+  it('you should be able to implment indexOf from scratch', function() {
+    expect(arraysExtraCreditAnswers.indexOf(a, 3)).to.eql(2);
+    expect(arraysExtraCreditAnswers.indexOf(a, 5)).to.eql(-1);
+  });
+
+  it('you should be able to implement push from scratch', function() {
+    var result = arraysExtraCreditAnswers.push(a, 10);
+
+    expect(result).to.eql(5)
+    expect(a).to.have.length(5);
+    expect(a[a.length - 1]).to.eql(10);
+  });
+
+  it('you should be able to implement pop from scratch', function() {
+    var result = arraysExtraCreditAnswers.pop(a);
+
+    expect(result).to.eql(4);
+    expect(a).to.have.length(3);
+    expect(a.join(' ')).to.eql('1 2 3');
+  });
+
+  it('you should be able to implement unshift from scratch', function () {
+    var result = arraysExtraCreditAnswers.unshift(a, 10);
+
+    expect(result).to.eql(5);
+    expect(a).to.have.length(5);
+    expect(a[0]).to.eql(10);
+  });
+
+  it('you should be able to implement shift from scratch', function () {
+    var result = arraysExtraCreditAnswers.shift(a);
+
+    expect(result).to.eql(1);
+    expect(a).to.have.length(3);
+    expect(a.join(' ')).to.eql('2 3 4');
+  });
+
+  it('you should be able to implement concat from scratch', function() {
+    var c = [ 'a', 'b', 'c', 1 ];
+    var result = arraysExtraCreditAnswers.concat(a, c);
+
+    expect(result).to.have.length(8);
+    expect(result.join(' ')).to.eql('1 2 3 4 a b c 1');
+  });
+
+});

tests/runner.html

@@ -29,6 +29,8 @@
   <!-- load tests and answers -->
   <script src="/tests/app/arrays.js"></script>
   <script src="/app/arrays.js"></script>
+  <script src="/tests/app/arraysExtraCredit.js"></script>
+  <script src="/app/arraysExtraCredit.js"></script>
   <script src="/tests/app/async.js"></script>
   <script src="/app/async.js"></script>
   <script src="/tests/app/bestPractices.js"></script>