javascript - 使用闭包和 IIF 创建对象实例

Question

我正在尝试学习创建对象和对象实例的最佳实践。我理解的一种方法是使用闭包返回一个全部包装为 IIF 的对象:

myApp2 = (function() {
  var count = 1;
  return {
    getCount: function(){return count},
    incCount: function(){count++}
  };
}())

var test = myApp2
console.log(test.getCount()); // outputs 1
console.log(test.incCount()); // increment count by 1
console.log(test.getCount()); // outputs 2
var test2 = myApp2            // I thought this would create new context
console.log(test2.getCount());// outputs 2, not 1 as expected

请纠正我的理解..

Answer 1

如果你想拥有不同的对象，你可以使用函数而不是 IIFE，并为每个对象调用一次:

function myApp2 () {
  var count = 1;
  return {
    getCount: function(){return count},
    incCount: function(){count++}
  };
}
var test = myApp2();
console.log(test.getCount()); // outputs 1
console.log(test.incCount()); // increment count by 1
console.log(test.getCount()); // outputs 2
var test2 = myApp2();         // creates new object
console.log(test2.getCount());// outputs 1