Javascript/デザインパターン/GoF/Singleton †
let instance;
class MySingleton {
constructor() {
if (!instance) {
this.val = 10;
instance = this;
}
return instance;
}
}
var c1 = new MySingleton();
var c2 = new MySingleton();
c1.val = 10;
c2.val = 20;
console.log(c1.val); // 20
