#23 - TypeScript & JavaScript

Roadmap/23 - SINGLETON/javascript/AChapeton.js

@@ -0,0 +1,40 @@
+const counter = () => {
+  var instance = null;
+  var count = 0;
+  function printCount() {
+      console.log("Numero de instancias activas: " + count);
+  }
+  function init() {
+      count++;
+      return {};
+  }
+  function createInstance() {
+      if (instance == null) {
+          instance = init();
+      }
+      return instance;
+  }
+  function closeInstance() {
+      count--;
+      instance = null;
+  }
+  return {
+      createInstance: createInstance,
+      closeInstance: closeInstance,
+      printCount: printCount
+  };
+}
+var foo = counter();
+foo.printCount();
+foo.createInstance();
+foo.printCount();
+foo.createInstance();
+foo.printCount();
+foo.createInstance();
+foo.printCount();
+foo.closeInstance();
+foo.printCount();
+foo.createInstance();
+foo.printCount();
+foo.closeInstance();
+foo.printCount();

Roadmap/23 - SINGLETON/typescript/AChapeton.ts

@@ -0,0 +1,54 @@
+interface fooType {
+  createInstance: () => {};
+  closeInstance: () => void;
+  printCount: () => void;
+}
+
+const counter = () => {
+
+  let instance: {} | null = null;
+  let count: number = 0;
+
+  function printCount() {
+      console.log("Numero de instancias activas: " + count);
+  }
+
+  function init() {
+      count++;
+      return {}
+  }
+
+  function createInstance() {
+      if (instance == null) {
+        instance = init();
+      }
+      return instance;
+  }
+
+  function closeInstance() {
+      count--;
+      instance = null;
+  }
+
+  return {
+      createInstance,
+      closeInstance,
+      printCount
+  }
+}
+
+let foo: fooType = counter();
+
+foo.printCount()  
+foo.createInstance()
+foo.printCount() 
+foo.createInstance()
+foo.printCount() 
+foo.createInstance()
+foo.printCount() 
+foo.closeInstance()
+foo.printCount() 
+foo.createInstance();
+foo.printCount();
+foo.closeInstance();
+foo.printCount();