javascript - 类型错误 : 'ownKeys' on proxy: trap result did not include 'arguments'

Question

它想从我这里得到什么？如何让它发挥作用？

var proxy_handler = 
{
    ownKeys: function(target)
    {
        return Object.keys(target.data)
    },
}

var proxxxy = function(initial_data)
{
    var return_value = "Goodbye world"
    var target = function() { return return_value }
    if(typeof initial_data == "undefined")
    {
        target.data = {}
    }
    else
    {
        target.data = initial_data
    }
    return new Proxy(target, proxy_handler)
}

var p = proxxxy({q:"aaa",w:"bbb",f:"ccc"})
console.log(p())
console.log(Object.getOwnPropertyNames(p))

它会打印一个错误，但它不应该:

me@me:~/tst$ node --version
v6.2.2
me@me:~/tst$ node test3.js 
Goodbye world
/home/me/tst/test3.js:26
    console.log(Object.getOwnPropertyNames(p))
                       ^

TypeError: 'ownKeys' on proxy: trap result did not include 'arguments'
    at Object.<anonymous> (/home/me/tst/test3.js:26:24)
    at Module._compile (module.js:541:32)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:458:32)
    at tryModuleLoad (module.js:417:12)
    at Function.Module._load (module.js:409:3)
    at Module.runMain (module.js:575:10)
    at run (node.js:348:7)
    at startup (node.js:140:9)
    at node.js:463:3

这是一个错误吗？如果是这样 - 我可以在哪里提交它？

Answer 1

这不是错误；此行为由 proxy spec 定义对于 ownKeys，步骤 17a。用简单的英语来说，实际 target 的任何不可配置属性都必须出现在 ownKeys 返回的属性列表中，因此缺少 arguments在你的例子中:

> Object.getOwnPropertyDescriptor(target, "arguments")
Object {value: null, writable: false, enumerable: false, configurable: false}