added closure example to decorators

robdodson · robdodson · commit fc6a4ebc8905 · 2012-08-30T19:49:05.000-07:00
diff --git a/decorator/sale-closures/index.html b/decorator/sale-closures/index.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Decorators: With Closures!</title>
+    <meta name="description" content="">
+    <meta name="author" content="">
+  </head>
+  <body>
+    <script type="text/javascript" src="main.js"></script>
+  </body>
+</html>
diff --git a/decorator/sale-closures/main.js b/decorator/sale-closures/main.js
@@ -0,0 +1,38 @@
+"use strict";
+
+function Sale(price) {
+    this.price = price || 100;
+}
+
+Sale.prototype.getPrice = function() {
+    return this.price;
+};
+
+Sale.prototype.setPrice = function(price) {
+    this.price = price;
+};
+
+function usd(fn, context) {
+    var price = fn.call(context);
+    return "$" + price;
+}
+
+function decorate(dec, fn, context) {
+    return function() {
+        return dec.call(context, fn, context);
+    };
+}
+
+var sale = new Sale(50);
+
+// Decorate our getPrice method. We'll just add
+// some extra dollar signs to the output.
+sale.getPrice = decorate(usd, sale.getPrice, sale);
+sale.getPrice = decorate(usd, sale.getPrice, sale);
+sale.getPrice = decorate(usd, sale.getPrice, sale);
+console.log(sale.getPrice()); // output: $$$50
+
+// Test to make sure other methods can still
+// access the price in the correct context
+sale.setPrice(100);
+console.log(sale.getPrice()); // output: $$$100
