对象返回自己的属性并保留方法

Question

I have an object that wraps some data:

function Obj1() {
    var _foo = 'bar'
    this.obj2 = {
        'b': 'c'
    }
    this.method = function() {
        return _foo
    }
}
var obj1 = new Obj1()

Now when I call console.log(obj1); I want it to show me object obj2 content. The trick is that I need to still be able to call obj1.method and get value of _foo . How do I do that if it's even possible? My thought was that sth like getter will be suitable, but can't figure out where and how to assign one.

Answer 1

if i understand correctly, you can use prototype

Example

function Obj1() {
    this.obj2 = {
        'b': 'c'
    }
}
Obj1.prototype.method = function() {
    return 'bar';
}

var obj1 = new Obj1();

//prints only properties
console.log(obj1);

//prints method result
console.log(obj1.method())

Answer 2

As far as I understood you're trying to hide method property. To achieve this, use Object.defineProperty . Function will not be logged because enumerable property is false by default which prevents property from showing in console.log for example.

 function Obj1() { var _foo = 'bar' this.obj2 = { 'b': 'c' } Object.defineProperty(this.obj2, 'method', { value: function() { return _foo; } }); return this.obj2; } var obj1 = new Obj1() console.log(obj1); console.log(obj1.method()); 

Answer 3

Since you calling new Obj1() . The result variable var obj1 is a class object and not a function, for you to get the value of obj2 you will have to call obj1.obj2 in your console log. If you want obj1 to hold the value of obj2. Then use the following code

function Obj1() {
    var obj2 = {
       'b': 'c'
    }
    return this.obj2;
}
var obj1 = Obj1();
console.log(obj1);

This will give you the required result in the console log, but the object will no longer be a class object and will have only the value of obj2.

Answer 4

Sticking to your original snippet a factory looks like a good option:

function factory() {
    var foo = 'bar';
    var props = { b: 'c'};
    var proto = {
        method: function() { return foo; }
    }; 
    var obj = Object.create(proto);
    Object.assign(obj, props);
    return obj;
}

var obj = factory();
console.log(obj); // {b: 'c'}
console.log(obj.method()) // 'foo'

You could even pass props as an argument to get a more flexible way of spawning objects with an " unenumerable " method accessing private members.