add another javascript test

2012-11-06 18:10:29 +00:00 · 2012-11-06 18:10:29 +00:00 · 16c1059723
parent 12f874cd92
commit 16c1059723
3 changed files with 83 additions and 0 deletions
--- a/test/js/index.html
+++ b/test/js/index.html
@ -23,5 +23,9 @@
 <li><a href="doc-dom1.html">Direct reference</a></li>
 <li><a href="doc-dom2.html">getElementById reference</a></li>
 </ul>
+<h2>Assorted</a>
+<ul>
+<li><a href="wikipedia-lcm.html">Example from wikipedia</a></li>
+</ul>
 </body>
 </html>
--- a/test/js/wikipedia-lcm.html
+++ b/test/js/wikipedia-lcm.html
@ -0,0 +1,9 @@
+<html>
+<head>
+<title>Wikipedia lcm script</title>
+</head>
+<body>
+<h1>Wikipedia lcm script</h1>
+<script src="wikipedia-lcm.js"></script>
+</body>
+</html>
--- a/test/js/wikipedia-lcm.js
+++ b/test/js/wikipedia-lcm.js
@ -0,0 +1,70 @@
+/* Finds the lowest common multiple (LCM) of two numbers */
+function LCMCalculator(x, y) { // constructor function
+    var checkInt = function (x) { // inner function
+        if (x % 1 !== 0) {
+            throw new TypeError(x + " is not an integer"); // throw an exception
+        }
+        return x;
+    };
+    this.a = checkInt(x)
+    // ^ semicolons are optional
+    this.b = checkInt(y);
+}
+// The prototype of object instances created by a constructor is
+// that constructor's "prototype" property.
+LCMCalculator.prototype = { // object literal
+    constructor: LCMCalculator, // when reassigning a prototype, set the constructor property appropriately
+    gcd: function () { // method that calculates the greatest common divisor
+        // Euclidean algorithm:
+        var a = Math.abs(this.a), b = Math.abs(this.b), t;
+        if (a < b) {
+            // swap variables
+            t = b;
+            b = a;
+            a = t;
+        }
+        while (b !== 0) {
+            t = b;
+            b = a % b;
+            a = t;
+        }
+        // Only need to calculate GCD once, so "redefine" this method.
+        // (Actually not redefinition—it's defined on the instance itself,
+        // so that this.gcd refers to this "redefinition" instead of LCMCalculator.prototype.gcd.)
+        // Also, 'gcd' === "gcd", this['gcd'] === this.gcd
+        this['gcd'] = function () {
+            return a;
+        };
+        return a;
+    },
+    // Object property names can be specified by strings delimited by double (") or single (') quotes.
+    "lcm" : function () {
+        // Variable names don't collide with object properties, e.g. |lcm| is not |this.lcm|.
+        // not using |this.a * this.b| to avoid FP precision issues
+        var lcm = this.a / this.gcd() * this.b;
+        // Only need to calculate lcm once, so "redefine" this method.
+        this.lcm = function () {
+            return lcm;
+        };
+        return lcm;
+    },
+    toString: function () {
+        return "LCMCalculator: a = " + this.a + ", b = " + this.b;
+    }
+};
+ 
+//define generic output function; this implementation only works for web browsers
+function output(x) {
+    document.body.appendChild(document.createTextNode(x));
+    document.body.appendChild(document.createElement('br'));
+}
+ 
+// Note: Array's map() and forEach() are defined in JavaScript 1.6.
+// They are used here to demonstrate JavaScript's inherent functional nature.
+[[25, 55], [21, 56], [22, 58], [28, 56]].map(function (pair) { // array literal + mapping function
+    return new LCMCalculator(pair[0], pair[1]);
+}).sort(function (a, b) { // sort with this comparative function
+    return a.lcm() - b.lcm();
+}).forEach(function (obj) {
+    output(obj + ", gcd = " + obj.gcd() + ", lcm = " + obj.lcm());
+});