Apollo-tooling: Custom scalars as a string instead of number

[yuricamara]

Hi,

I have some custom scalars in my NodeJS backend.

package.json
"graphql": "0.11.7",
"graphql-server-express": "1.3.2",
"graphql-tools": "2.14.1",

One of them is Tel which represents a phone number.

See an example:

// This is an output from apollo-codegen
communications:  {
      phones: Array< string | null > | null,
}

// But I would expect this with my custom scalar Tel
communications:  {
      phones: Array< number | null > | null,
}

Is it possible?

[lewisf]

There is a path forward where we generate global type identifiers that we expect consumers to implement (and put in the type search path of flow).

would that suffice?

[lanwin]

wouldn't it be better if the generator stops at each scalar and make you provide a mapping as parameter?

something like --map PhoneNumberType:Array<number|null>|null

[yuricamara]

@lewisf , I didn't understand your answer. Sorry!

[alex-zer0]

@yuricamara Have you found the solution?
I've faced with the same issue.

[yuricamara]

Not yet, @alex-zer0

[gviligvili]

Hey, we would like to use the codegen feature but that issue is the only thing that breaks our interfaces.
Any news about it?

[mike-marcacci]

What language target is missing this feature? I know it’s existed in Flow and TypeScript for a long time now...

[gviligvili]

Im sorry, i cant seem to find documentation on it, any refrences please:)?

[mike-marcacci]

If you use the option --passthroughCustomScalars, apollo-cli will use the name of your custom scalar as its flow/typescript name, so in your case Tel.

You can then define a global type Tel in your app. If you want to avoid name conflicts, also use --customScalarsPrefix=customScalarsPrefix to define a prefix. Using the prefix GraphQL_ would write your type as GraphQL_Tel.

[asfernandes]

If you use the option --passthroughCustomScalars, apollo-cli will use the name of your custom scalar as its flow/typescript name, so in your case Tel.

You can then define a global type Tel in your app. If you want to avoid name conflicts, also use --customScalarsPrefix=customScalarsPrefix to define a prefix. Using the prefix GraphQL_ would write your type as GraphQL_Tel.

How to make it work when that typename is from a module (must be imported)?

[LinusU]

@asfernandes you should be able to create a .d.ts file that defines your scalars:

globalScalars.d.ts

import { Foobar } from 'foobar'

type GraphQL_Foobar = Foobar
type GraphQL_Date = string
type GraphQL_DateTime = string

with

--passthroughCustomScalars --customScalarsPrefix=GraphQL_

[asfernandes]

@asfernandes you should be able to create a .d.ts file that defines your scalars:

globalScalars.d.ts

import { Foobar } from 'foobar'

@LinusU when you use import, your decl file become modular and the generated files do not import it.

I had resolved this problem using an additional file, but it's ugly.

[asfernandes]

@LinusU I have tried another approach and seems to work. Should it be declared this way?

import { LocalDate, LocalDateTime } from 'js-joda';

declare global {
    type GraphQLLong = number;
    type GraphQLLocalDate = LocalDate;
    type GraphQLLocalDateTime = LocalDateTime;
}

[LinusU]

when you use import, your decl file become modular and the generated files do not import it.

Ah, right... Hmm, I wonder why it does work for me though? 🤔

Anyhow, the correct way is probably to use /// <reference types="..." />