javascript js通用单例设计

Posted 2021-05-03

// 传入的fn用于具体生成实例对象，在单例中可以避免重复生成

function getSingleton(fn) {
	var instance = null;
	return function () {
		return instance || (instance = fn.apply(null, arguments));
	};
}

let IdGenerator = (function () {
    let instance;
    let counter = 0;
    return class { // 返回一个匿名class
        constructor() {
            if (!instance) {
                instance = this;
            }
            return instance;
        }
        newId() {
            return ++counter;
        }
    }
})();