3 ms·
__proto__ is an old, deprecated feature of JavaScript. The proper way to get the prototype of an object is with Object.getPrototypeOf(object) and use Object.set
by NathanKP 13y ago
__proto__ is an old, deprecated feature of JavaScript. The proper way to get the prototype of an object is with Object.getPrototypeOf(object) and use Object.setPrototypeOf(object) to set a prototype.
I'm assuming in this example what the web app is doing is it is using the name of the child as the key in a object like this:
students[studentName] = studentDetails;
Since the child's name is __proto__ the web app is setting:
students['__proto__'] = studentDetails;
Which is the same as:
students.__proto__ = studentDetails;
Which sets the prototype of the object full of students to the student's details, and will totally break things.
There is no reason to use a library like stringset.js or stringmap.js with extra overhead. The proper solution is to never use user supplied strings as keys in an object. A good key to use in this situation for an object full of students would be a generated student ID or something like that.
- olov 13y agoFor many problems, you never need a stringmap (in any language so JS). For a lot of problems, you do. Perhaps the administrative software for this school wanted to display the most popular names in each class, which you'd typically do with a stringmap and many would mistakenly do with an object. That's the same problem as counting word frequencies in a sentence. __proto__ bugs are a real thing, and it affects small and large apps (Google Apps comes to mind).
- NathanKP 13y agoTrue. Those are both examples of problems where a string map using user supplied strings as keys would be the best solution to the problem.