父级继承自子级 - JavaScript

Question

Really confused here, checkout the image above. Why the parent a is inheriting something that i defined for its child?

Answer 1

in javascript when you assign an object variable as a variable it is a reference to a single object just like arrays. so instead of being a copy of the object it is pointing to the original object in memory. this means that both a and b are pointing to the same object in memory. any action taken on one variable will effect the other since they are pointing to the same instance of the object.