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It is actually quite frustrating compared to some other languages, and more often than not you see that its just `JSON.parse` and hope for the best. I wish we h

It is actually quite frustrating compared to some other languages, and more often than not you see that its just `JSON.parse` and hope for the best. I wish we had something like Rust's Serde or Haskell's aeson. If you want to validate data coming over IO then your options are data validation libraries such joi, io-ts, and yup. You have to write seperate data validators on top of your types. io-ts has a way of deriving types from validators, but io-ts is often seen as quite intimidating being built on top of fp-ts. No matter how carefully you maintain strict typing within your typscript project the moment you hit IO everything is basically `any`. Some projects like openapi-generator might generate some validators for server respones, but I've not seen any good generators that do actual validation. I'm not sure if apollo-graphql does responses validation? Does anyone know?

willberman 7y ago
I second the use of iots. It has a decent learning curve but is very worth it in the end.
eropple 7y ago
Plenty of web frameworks can validate via JSON Schema, using ajv under the hood. (I use Fastify.) io-ts is pretty scary, though. I like the `runtypes` library but it doesn't help me express my types in a way clients can consume, which, enh.
- Kinrany 7y ago
  I also liked runtypes more, but it turns out composing io-ts codecs is perfectly readable, and being able to deserialize at the same time/instead of validating is very convenient. Caveat, I've only been using it for two weeks.
Ezku 7y ago
My personal take is that io-ts _is_ typescript’s aeson, but if you’re scared of the baggage it comes with then how about giving zod a try? https://github.com/vriad/zod https://github.com/vriad/zod
seer 7y ago
Apollo does indeed validate responses as well as requests. If your server tries to send an object that doesn’t match the schema, you’re going to return just a 500 error, which means your clients can trust the graphql types implicitly. Since in my current job I can’t use graphql but have to type everything in openapi, Had to resort to writing my own lib to get to the same functionality for a REST backend in TS - https://github.com/ovotech/laminar https://github.com/ovotech/laminar

willberman 7y ago

I second the use of iots. It has a decent learning curve but is very worth it in the end.

eropple 7y ago

Plenty of web frameworks can validate via JSON Schema, using ajv under the hood. (I use Fastify.) io-ts is pretty scary, though. I like the `runtypes` library but it doesn't help me express my types in a way clients can consume, which, enh.

Kinrany 7y ago
I also liked runtypes more, but it turns out composing io-ts codecs is perfectly readable, and being able to deserialize at the same time/instead of validating is very convenient. Caveat, I've only been using it for two weeks.

Ezku 7y ago

My personal take is that io-ts _is_ typescript’s aeson, but if you’re scared of the baggage it comes with then how about giving zod a try? https://github.com/vriad/zod https://github.com/vriad/zod

seer 7y ago

Apollo does indeed validate responses as well as requests. If your server tries to send an object that doesn’t match the schema, you’re going to return just a 500 error, which means your clients can trust the graphql types implicitly. Since in my current job I can’t use graphql but have to type everything in openapi, Had to resort to writing my own lib to get to the same functionality for a REST backend in TS - https://github.com/ovotech/laminar https://github.com/ovotech/laminar