Why is NodeList not an array?

NodeList objects are very similar in some ways and arrays, and it appears that you can directly use methods inherited from Array.prototype. However, in addition to the Foreach method, NodeList does not have these array-like methods.

The inheritance mechanism of JavaScript is prototype-based. Array elements have some array methods (such as ForEach and map) because they have these methods on the prototype chain, as follows:

MyArray---array.prototype------null (to get the prototype chain of an object, you can call object.getprototypeof continuously until the end of the prototype chain) ).

ForEach, map These methods are actually array.prototype the object.

And the array is different, NodeList's prototype chain is like this:

Mynodelist--Nodelist.prototype--object.prototype--NULL

NodeList's prototype has a Item,entries,keys and values method in addition to the array-like foreach method.

Why is NodeList not an array?