Inconsistent type-checking for input arguments

[michaelbridge]

In both cases, junk is an invalid argument, while id is valid. As you can see in the 2nd example, type-checking does not correctly identify junk as an invalid parameter. This issue also exists within more complicated JSON inputs, but this is the simplest reproduction.

The generated type is as follows:

company<Args extends VariabledInput<{
    id: number,
}>, ...

I experimented with several solutions but have thus far been unsuccessful. The solution I thought would work did not -- this involves wrapping VariabledInput with Exact (per type-fest):

company<Args extends Exact<VariabledInput<{
    id: number,
}>, Args>, ...

Thoughts? Hints? Suggestions?

[spion]

Unfortunately not much I can do - Args extends VariabledInput<argsType> is necessary to be able to accept variables in any position of argsType, however, extends also implies "additional properties available".

An alternative design that I was playing with but never got a chance to make work

query<{myVar: string}>('QueryName', (q, vars) => [
  q.company({id: vars.myVar}, c => [c.display_name, c.investments(all)])
])

Runtime details: a proxy is passed where any get accessor always returns a variable (with the name of the accessor)

Pros

• no need for generics, it can simply be VariabledInput
• no more problems with infinite recursion for some complex (e.g. Hasura) types
• much simpler generated code

Cons

• slightly more verbose
• slightly weirder
• probably no type inference for variables (generic has to be predeclared)
• need to import the right input type (including scalars) when writing queries.
• large, backward incompatible change in the design

[spion]

Looks like I was wrong

continent<
    Args extends VariabledInput<{
      code: string
    }>,
    Sel extends Selection<Continent>
  >(
    args: Args & { [K in keyof Args]: K extends keyof { code: string } ? Args[K] : never },
    selectorFn: (s: Continent) => [...Sel]
  )

has the desired behavior. Haven't tried yet if it will work in all situations.

[spion]

PR: https://github.com/typed-graphql-builder/typed-graphql-builder/pull/67 - existing tests pass.