如何从JavaScript对象中删除setter？

Question

Consider the following code:

var x = 0;

var o = {};

function getter() {
    return x;
}

Object.defineProperty(o, "y", {
    get: getter,
    set: function (y) {
        x = y;

        Object.defineProperty(o, "y", {
            get: getter
        });
    },
    configurable: true
});

My objective is to remove the setter and make the property oy non-configurable after the setter has been called once. However it doesn't work as expected:

> x       // 0
> o.y     // 0
> o.y = 1 // 1
> x       // 1
> o.y     // 1
> o.y = 2 // 2
> x       // 2
> o.y     // 2

So my code did not work as expected, and I can't think of any other solution. Hence this question.

Answer 1

Think of the redefine operation like this: each key in the new definition replaces the corresponding key in the old definition. Since you do not specify a set key when you redefine the property, it retains its old value.

You need to explicitly include it as undefined in order to get rid of it, and in fact you don't need to set the getter at all because you are not changing it:

Object.defineProperty(o, "y", {
    set: undefined
});

Then, in my tests:

o.y     // 0
o.y = 1
o.y     // 1
o.y = 2
o.y     // 1