Add polymorphic callback with unit tests

callbackPolymorphic.js

@@ -0,0 +1,33 @@
+var commaDelimiter = require('./commaDelimiter');
+var pipeDelimiter = require('./pipeDelimiter');
+
+buildFerociousCats({ list: '', delimiter: commaDelimiter }, 'Panther', getJaguar);
+buildFerociousCats({ list: '', delimiter: pipeDelimiter }, 'Panther', getJaguar);
+
+function getJaguar(cat) {
+  buildFerociousCats(cat, 'Jaguar', getLynx);
+}
+
+function getLynx(cat) {
+  buildFerociousCats(cat, 'Lynx', getSnowLeopard);
+}
+
+function getSnowLeopard(cat) {
+  buildFerociousCats(cat, 'Snow Leopard', getLion);
+}
+
+function getLion(cat) {
+  buildFerociousCats(cat, 'Lion', printList);
+}
+
+function printList(cat) {
+  console.log(cat.list);
+}
+
+function buildFerociousCats(cat, returnValue, next) {
+  setTimeout(function asyncCall(data) {
+    var catList = cat.delimiter(cat.list, data);
+
+    next({ list: catList, delimiter: cat.delimiter });
+  }, 1, returnValue);
+}

commaDelimiter.js

@@ -0,0 +1,5 @@
+function commaDelimiter(list, cat) {
+  return list === '' ? cat : list + ',' + cat;
+}
+
+module.exports = commaDelimiter;

package.json

@@ -11,7 +11,7 @@
     "test": "node_modules/.bin/mocha --ui bdd test/**/*.js",
     "callback-hell": "node callbackHell.js",
     "dependency-inversion": "node callbackDependencyInversion.js",
-    "polymorphic-callback": "node callbackPoloymorphic.js"
+    "polymorphic-callback": "node callbackPolymorphic.js"
   },
   "devDependencies": {
     "mocha": "3.0.1",

pipeDelimiter.js

@@ -0,0 +1,5 @@
+function pipeDelimiter(list, cat) {
+  return list === '' ? cat : list + '|' + cat;
+}
+
+module.exports = pipeDelimiter;

test/commaDelimiter.test.js

@@ -0,0 +1,18 @@
+var commaDelimiter = require('../commaDelimiter');
+var describe = require('mocha/lib/mocha.js').describe;
+var it = require('mocha/lib/mocha.js').it;
+var assert = require('chai').assert;
+
+describe('A pipe delimiter', function () {
+  it('does not add pipe with an empty list', function () {
+    var list = commaDelimiter('', 'Cat');
+
+    assert.equal(list, 'Cat');
+  });
+
+  it('adds a pipe in the list', function () {
+    var list = commaDelimiter('Cat', 'Cat');
+
+    assert.equal(list, 'Cat,Cat');
+  });
+});

test/pipeDelimiter.test.js

@@ -0,0 +1,18 @@
+var pipeDelimiter = require('../pipeDelimiter');
+var describe = require('mocha/lib/mocha.js').describe;
+var it = require('mocha/lib/mocha.js').it;
+var assert = require('chai').assert;
+
+describe('A pipe delimiter', function () {
+  it('does not add pipe with an empty list', function () {
+    var list = pipeDelimiter('', 'Cat');
+
+    assert.equal(list, 'Cat');
+  });
+
+  it('adds a pipe in the list', function () {
+    var list = pipeDelimiter('Cat', 'Cat');
+
+    assert.equal(list, 'Cat|Cat');
+  });
+});