[feature] decoder functions

[scottc]

In a perfect world, everyone would version their immutable apis and never introduce breaking changes.

But in reality co-workers could introduce breaking api changes.

There could potentially be a mismatch between the actual runtime json response and the static compile time typescript types.

This can cause runtime errors, but could be caught by the typechecker / developer at compile time.

So a good solution is to implement decoder functions at the boundaries of the application, which are run-time type checks, with some static types on top.

If the run-time type check fails, the endpoint could return an error, in the form of a boxed result type.

Some examples and helper libraries:

https://github.com/nvie/decoders
https://github.com/swissmanu/spicery
https://github.com/gcanti/io-ts
https://github.com/fabiandev/ts-runtime

[mtennoe]

This is a great idea! Would definitely add an extra layer of protection.
Some things we should ensure (imo):

• It needs to be optional in case consumers don't want the decoders for whatever reason
• It needs to be lightweight to not bloat the consumers generated bundle sizes
• It needs to have some level of configurability - for instance on what level to throw errors (errors, warnings, etc), and probably some pluggable way to handle errors when they happen