Getter在空值上返回整个函数

Question

I've created a simple storage object to store a name with setters and getters. However, trying to fetch the name before it is set returns the function? I would want it to return null

name: function (val) {
    var value = val;

    this.__defineGetter__('value', function () {
        if (value == null) return null;
        return value;
    });

    this.__defineSetter__('value', function(val) {
        value = val;
    });
},

For the full code:

http://jsfiddle.net/GKC4P/2/

Answer 1

Try this way. You don't need getters or setters

var storage = {};

Object.defineProperty(storage, 'name', {
   value : null,
   writable: true

});

alert(storage.name);
storage.name = 'Bob';
alert(storage.name);

This will also work the same way.

Answer 2

name is a method of your storage object - which when called creates a setter/getter for the .value property. What you want is

var storage = {};
var value = val;
storage.__defineGetter__('name', function () {
    if (value == null) return null;
    return value;
});
storage.__defineSetter__('name', function(val) {
    value = val;
});

Or with proper Object.defineProperty and an IEFE for making value local:

var storage = (function() {
    var value = val;
    return Object.defineProperty({}, 'name', {
        get: function () {
            if (value == null) return null;
            return value;
        },
        set: function(val) {
            value = val;
        }
   });
}());