Javascript对象：对属性名称的反向引用

2023年1月27日 170次阅读

我正在尝试简化
javascript对象内容的创建,以便值取决于成员名称,如下所示：

var obj = {
    1: "you selected 1",
    2: "wow, you selected 2",
    3: "this time, you selected " + myName(), //myName() gets resolved to 3
    137: "I think you've chosen " + myName() + " this time.", //myName() gets resolved to 137
    513: myName() + " is the answer!" //myName() gets resolved to 513
};

是否可以在值的定义中反向引用成员名称,使用像假设的函数myName()一样的思考？

如果不存在本机方法,建议的方法是什么？

您可能会问“为什么这个人需要这种生成对象的方法？”,答案是：在我的代码中,成员/字段名称可能会更改,默认值将被复制,唯一的区别是对成员的引用name,我不想在每个键值对中定义数值两次,因此我采用了一种在值定义中反向引用名称的方法.

最佳答案 您正在寻找ES6功能,
Proxy

The Proxy object is used to define custom behavior for fundamental operations (e.g. property lookup, assignment, enumeration, function invocation, etc).

然后使用实际键获取prop,并用实际键替换占位符{key}.

var obj = {
        1: "you selected {key}",
        2: "wow, you selected {key}",
        3: "this time, you selected {key}",
        137: "I think you've chosen {key} this time.",
        513: "{key} is the answer!"
    },
    p = new Proxy(obj, {
        get: function(target, prop) {
            return target[prop] && target[prop].replace("{key}", prop);
        }
    });

console.log(p[3]);          // this time, you selected 3
console.log(p[137]);        // I think you've chosen 137 this time.
console.log(p[513]);        // 513 is the answer!
obj.foo = 'This is {key}!'; // create new property foo
console.log(p.foo);         // This is foo!
obj.bar = obj.foo;          // assign foo to bar
delete obj.foo;             // delete foo
console.log(p.foo);         // undefined
console.log(p.bar);         // This is bar!
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