How to get __proto__ in NodeJS?

Question

So when i declare an array as var arr = [] in browser console and then do arr.__proto__ i get the prototype in console.

Browser Javascript

But when i do the same thing in nodeJs i get [] as result.

NodeJs

Nodejs is javascript running on server so why is the result not same . Am i missing something ? How do i access the prototype in nodeJs and get the same result.

Answer 1

What you are seeing is simply a quirk due to display differences. arr.__proto__ points to the exact same object in both cases - Array.prototype - it's just that your browser and Node present the object to the user for display differently.

You already can access, for example, arr.__proto__.fill in Node, even though it's not displayed in the console when logging arr.__proto__. You can iterate over the properties manually to display them if you want:

const arr = [];
Object.getOwnPropertyNames(arr.__proto__).forEach((key) => {
  console.log(key);
});

The above will show you the exact same results in both environments.

If you hook up Node to Chrome's console, you'll see that console.log(arr.__proto__) looks exactly the same when looking at the log from Node in Chrome, and when looking at the log from a webpage in Chrome.

But, do note that __proto__ is deprecated - you should prefer to use Object.getPrototypeOf nowadays.