Demo triển khai singleton pattern trên Javacript Live code

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Singleton Javascript</title>
</head>

<body>
    <p>Bật console của trình duyệt lên để xem log</p>
    <script>
    var mySingleton = (function () {

var instance;

function init() {

function privateMethod() {
                return 'private method';
            }

var privateVariable = "private property";

return {

publicMethod: function () {
                    return 'public method';
                },

publicProperty: "public property",

getPrivateMethod: function () {
                    return privateMethod();
                }

};

return {
            getInstance: function () {

if (!instance) {
                    instance = init();
                }

return instance;
            }

};

})();

//use
    var myInstance = mySingleton.getInstance();

console.log(myInstance.publicMethod()); 
    console.log(myInstance.publicProperty);
    console.log(myInstance.getPrivateMethod());

</script>
</body>

</html>