如何在JavaScript中索引原型对象

Question

So last I tried to index a prototype object (eg: String.prototype ) using a for...in statement I was able to get all its methods and properties.

But now I seem to be unable to index the prototype as I`ve tried recently.

let stringProto = String.prototype;
for (let i in stringProto)
    console.log(i) // code not running, why? :'(

I've checked if the prototype is iterable using Symbol.iterator and it is but it still does not index its properties.

GOAL

I want to be able to index each method/ property of a prototype object in JavaScript (I`m going to back them up in a separate private object).

REASON :

• It's for a JavaScript library I`m working on: https://github.com/LapysDev/LapysJS .
• Useful for preventing edge-cases like this: String.prototype.replace = null from getting in the way of running your code.

Answer 1

Built-in prototype methods aren't iterable (see the spec).

Instead, use getOwnPropertyNames() .