Two options for js singleton mode_javascript skills

Option 1: Using the two functions of closure, the internal variables can be read flexibly, and the second is to keep these variables in the memory.

Copy code The code is as follows:

//Option 1
var SingletonTester = (function { Another way is to return the object
this.pointX = args.pointX || 6;
this.pointY = args.pointY || 10;
}

//Single instance
var instance;

//return object
return {
name: 'SingletonTester',

getInstance: function (args) {
                 if (instance = == undefined) {
                       instance = new Singleton(args);                                                                          
})(); //Execute this method directly

//Test
var test = SingletonTester.getInstance({ pointX: 5 });
console.log(test.pointX);




Option 2:

Copy code

The code is as follows:

//Option 2 function Universe() { // Determine whether an instance exists if (typeof Universe.instance === 'object') { return Universe.instance; }

// Other content
this.start_time = 0;
this.bang = "Big";

// Cache
Universe.instance = this;

// Implicitly return this
}

// Test
var uni = new Universe();
var uni2 = new Universe();
console.log(uni === uni2); // true