Why JSON.stringify() returns empty result for some objects

Question

This question is so basic, yet I have no idea of the answer.

Why screen object when stringified returns empty?

Does this mean JSON.stringify() needs read/write access to the input?

let a = {foo: 'one', bar: 2};


console.log(JSON.stringify(a));
console.log(JSON.stringify(screen));

Answer 1

FROM MDN Network

For all the other Object instances (including Map, Set, WeakMap and WeakSet), only their enumerable properties will be serialized.

Read https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable

    console.log((window.screen));
    console.log(JSON.stringify(window.screen));
    console.log(window.propertyIsEnumerable(screen));