我有一个像这样的对象:

const foo = {
  bar: 'bar'
};


我想对其进行修改,以便如果有人尝试访问不存在的属性,则会引发错误,而不是返回未定义的错误。

例如,

const baz = foo.baz;
// Error: Property 'baz' does not exist on object 'foo'


这可能吗?

最佳答案

借助ECMAScript 6,您可以使用代理。

var original = {"foo": "bar"};
var proxy = new Proxy(original, {
    get: function(target, name, receiver) {
        console.log("Name of requested property: " + name);
        var rv = target[name];
        if (rv === undefined) {
          console.log("There is no such thing as " + name + ".")
          rv = "Whatever you like"
        }
        return rv;
    }
});

console.log("original.foo = " + proxy.foo);     // "bar"
console.log("proxy.foo = " + proxy.whatever);   // "Whatever you like"


https://jsfiddle.net/u5b3wx9w/

07-24 09:44
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