feat(ts-client): optional custom scalars (#768)

Author: jasonkuhrt

src/generator/code/code.ts

@@ -17,6 +17,9 @@ export interface Input {
   importPaths?: {
     customScalarCodecs?: string
   }
+  /**
+   * The GraphQL SDL source code.
+   */
   schemaSource: string
   options?: {
     /**
@@ -32,16 +35,19 @@ export interface Input {
 
 export interface Config {
   schema: GraphQLSchema
+  typeMapByKind: TypeMapByKind
   libraryPaths: {
     schema: string
     scalars: string
   }
   importPaths: {
     customScalarCodecs: string
   }
-  typeMapByKind: TypeMapByKind
-  TSDoc: {
-    noDocPolicy: 'message' | 'ignore'
+  options: {
+    customScalars: boolean
+    TSDoc: {
+      noDocPolicy: 'message' | 'ignore'
+    }
   }
 }
 
@@ -57,8 +63,11 @@ export const resolveOptions = (input: Input): Config => {
       schema: input.libraryPaths?.schema ?? `graphql-request/alpha/schema`,
     },
     typeMapByKind: getTypeMapByKind(schema),
-    TSDoc: {
-      noDocPolicy: input.options?.TSDoc?.noDocPolicy ?? `ignore`,
+    options: {
+      customScalars: input.options?.customScalars ?? false,
+      TSDoc: {
+        noDocPolicy: input.options?.TSDoc?.noDocPolicy ?? `ignore`,
+      },
     },
   }
 }

src/generator/code/scalar.ts

@@ -3,22 +3,42 @@ import type { Config } from './code.js'
 export const generateScalar = (config: Config) => {
   let code = ``
 
+  // todo test case for when this is true
+  const needsDefaultCustomScalarImplementation = config.typeMapByKind.GraphQLScalarTypeCustom.length > 0
+    && !config.options.customScalars
+
   code += `
-    import type * as CustomScalar from '${config.importPaths.customScalarCodecs}'
+
+  ${config.options.customScalars ? `import type * as CustomScalar from '${config.importPaths.customScalarCodecs}'` : ``}
 
     declare global {
       interface SchemaCustomScalars {
         ${
     config.typeMapByKind.GraphQLScalarTypeCustom
       .map((_) => {
-        return `${_.name}: CustomScalar.${_.name}`
+        return `${_.name}: ${needsDefaultCustomScalarImplementation ? `String` : `CustomScalar.${_.name}`}`
       }).join(`\n`)
   }
       }
     }
 
     export * from '${config.libraryPaths.scalars}'
-    export * from '${config.importPaths.customScalarCodecs}'
+    ${config.options.customScalars ? `export * from '${config.importPaths.customScalarCodecs}'` : ``}
   `
+
+  if (needsDefaultCustomScalarImplementation) {
+    console.log(
+      `WARNING: Custom scalars detected in the schema, but you have not created a custom scalars module to import implementations from.`,
+    )
+    code += `
+${
+      config.typeMapByKind.GraphQLScalarTypeCustom
+        .flatMap((_) => {
+          return [`export const ${_.name} = String`, `export type ${_.name} = String`]
+        }).join(`\n`)
+    }
+    `
+  }
+
   return code
 }

src/generator/code/schemaBuildtime.ts

@@ -176,7 +176,7 @@ const concreteRenderers = defineConcreteRenderers({
 
 const getDocumentation = (config: Config, node: Describable) => {
   const generalDescription = node.description
-    ?? (config.TSDoc.noDocPolicy === `message` ? defaultDescription(node) : null)
+    ?? (config.options.TSDoc.noDocPolicy === `message` ? defaultDescription(node) : null)
 
   const deprecationDescription = isDeprecatableNode(node) && node.deprecationReason
     ? `@deprecated ${node.deprecationReason}`
@@ -191,7 +191,7 @@ const getDocumentation = (config: Config, node: Describable) => {
           : null
         const generalDescription = _.description
           ? _.description
-          : config.TSDoc.noDocPolicy === `message`
+          : config.options.TSDoc.noDocPolicy === `message`
           ? `Missing description.`
           : null
         if (!generalDescription && !deprecationDescription) return null

src/generator/files.ts

@@ -3,12 +3,12 @@ import { getPath } from '@dprint/typescript'
 import _ from 'json-bigint'
 import fs from 'node:fs/promises'
 import * as Path from 'node:path'
-import { errorFromMaybeError } from '../lib/prelude.js'
+import { fileExists } from '../lib/prelude.js'
 import { generateCode, type Input as GenerateInput } from './code/code.js'
 
 export interface Input {
   outputDirPath: string
-  code?: Omit<GenerateInput, 'schemaSource' | 'sourceDirPath'>
+  code?: Omit<GenerateInput, 'schemaSource' | 'sourceDirPath' | 'options'>
   sourceDirPath?: string
   schemaPath?: string
   format?: boolean
@@ -19,38 +19,29 @@ export const generateFiles = async (input: Input) => {
   const schemaPath = input.schemaPath ?? Path.join(sourceDirPath, `schema.graphql`)
   const schemaSource = await fs.readFile(schemaPath, `utf8`)
 
-  const customScalarCodecsPath = Path.relative(input.outputDirPath, Path.join(sourceDirPath, `customScalarCodecs.js`))
   // todo support other extensions: .tsx,.js,.mjs,.cjs
-  const customScalarCodecsPathExists = await fileExists(customScalarCodecsPath.replace(`.js`, `.ts`))
+  const customScalarCodecsFilePath = Path.join(sourceDirPath, `customScalarCodecs.ts`)
+  const customScalarCodecsImportPath = Path.relative(
+    input.outputDirPath,
+    customScalarCodecsFilePath.replace(/\.ts$/, `.js`),
+  )
+  const customScalarCodecsPathExists = await fileExists(customScalarCodecsFilePath)
   const formatter = (input.format ?? true) ? createFromBuffer(await fs.readFile(getPath())) : undefined
 
-  const options: GenerateInput['options'] = {
-    formatter,
-    customScalars: customScalarCodecsPathExists,
-  }
-
   const code = generateCode({
     schemaSource,
     importPaths: {
-      customScalarCodecs: customScalarCodecsPath,
+      customScalarCodecs: customScalarCodecsImportPath,
     },
     ...input.code,
-    options,
+    options: {
+      formatter,
+      customScalars: customScalarCodecsPathExists,
+    },
   })
   await fs.mkdir(input.outputDirPath, { recursive: true })
   await fs.writeFile(`${input.outputDirPath}/Index.ts`, code.index, { encoding: `utf8` })
   await fs.writeFile(`${input.outputDirPath}/SchemaBuildtime.ts`, code.schemaBuildtime, { encoding: `utf8` })
   await fs.writeFile(`${input.outputDirPath}/Scalar.ts`, code.scalars, { encoding: `utf8` })
   await fs.writeFile(`${input.outputDirPath}/SchemaRuntime.ts`, code.schemaRuntime, { encoding: `utf8` })
 }
-
-const fileExists = async (path: string) => {
-  return Boolean(
-    await fs.stat(path).catch((_: unknown) => {
-      const error = errorFromMaybeError(_)
-      return `code` in error && typeof error.code === `string` && error.code === `ENOENT`
-        ? null
-        : Promise.reject(error)
-    }),
-  )
-}

src/lib/prelude.ts

@@ -173,3 +173,16 @@ export type GetKeyOr<T, Key, Or> = Key extends keyof T ? T[Key] : Or
 import type { ConditionalSimplifyDeep } from 'type-fest/source/conditional-simplify.js'
 
 export type SimplifyDeep<T> = ConditionalSimplifyDeep<T, Function | Iterable<unknown> | Date, object>
+
+import fs from 'node:fs/promises'
+
+export const fileExists = async (path: string) => {
+  return Boolean(
+    await fs.stat(path).catch((_: unknown) => {
+      const error = errorFromMaybeError(_)
+      return `code` in error && typeof error.code === `string` && error.code === `ENOENT`
+        ? null
+        : Promise.reject(error)
+    }),
+  )
+}