prevent prototype pollution when parsing response bodies

[mvayngrib]

e.g. https://github.com/fastify/secure-json-parse (h/t @633kh4ck), but maybe something more performant per platform, e.g. removing __proto__ on the native side in react native

[ChALkeR]

Parsing json bodies does not pollute the prototype

Traversing response bodies and removing arbitrary values is... suboptimal and can cause issues on it's own

Instead we should perhaps add schemas for expected APIs and use those shemas as shapers, removing everything unexpected

So we could do a fetch-with-schema and require using that

[mvayngrib]

interesting idea, but kind of limiting. It prevents us from adding new fields without breaking old clients 🤔

[ChALkeR]

@mvayngrib no, it doesn't -- old clients will just have new fields removed

so this only will break if some fields client expects would be of unexpected type
... which would likely break the clients anyway, just in a less visible way

also, we had this idea for a while 😉 so it's not new

[mvayngrib]

old clients will just have new fields removed

ah i see. Still, this seems like something we'll need to slowly adopt across a large codebase. I was hoping we could secure JSON.parse itself better in a single place. What side effects could there be from removing '__proto__' from parseable fields?