[Feature] Add Support for Directive filters and Type filters to cover AWS AppSync use-cases

src/builder.ts

@@ -159,6 +159,7 @@ import {
   NexusDirectiveDef,
 } from './definitions/directive'
 import { rebuildNamedType, RebuildConfig } from './rebuildType'
+import type { Filters } from './printSchemaWithDirectives'
 
 type NexusShapedOutput = {
   name: string
@@ -324,6 +325,11 @@ export interface BuilderConfigInput {
   plugins?: NexusPlugin[]
   /** Provide if you wish to customize the behavior of the schema printing. Otherwise, uses `printSchema` from graphql-js */
   customPrintSchemaFn?: typeof printSchema
+  /** Add filters to skip defining directives / types for the usecase when they are already available within the environment for e.g
+   * with AWS AppSync, we have scaler type `AWS Timestamp` already defined, similary directives like `aws_lambda` are already
+   * available etc.
+   */
+  filters?: Filters
   /** Customize and toggle on or off various features of Nexus. */
   features?: NexusFeaturesInput
   /**

src/makeSchema.ts

@@ -162,6 +162,7 @@ function extractGraphQLSchemaOptions(
     sourceTypes,
     prettierConfig,
     plugins,
+    filters,
     customPrintSchemaFn,
     features,
     contextType,

src/printSchemaWithDirectives.ts

@@ -31,18 +31,28 @@ import {
 
 import { astFromValue } from 'graphql'
 
-export function printSchemaWithDirectives(schema: GraphQLSchema): string {
-  return printFilteredSchemaWithDirectives(schema, (n) => !isSpecifiedDirective(n), isDefinedType)
+type DirectiveFilter = (directive: GraphQLDirective) => boolean
+type TypeFilter = (type: GraphQLNamedType) => boolean
+
+export type Filters = {
+  isEnvironmentDefinedDirective?: DirectiveFilter
+  isEnvironmentDefinedType?: TypeFilter
 }
 
-function isDefinedType(type: GraphQLNamedType): boolean {
-  return !isSpecifiedScalarType(type) && !isIntrospectionType(type)
+export function printSchemaWithDirectives(schema: GraphQLSchema, filters?: Filters): string {
+  const directiveFilter: DirectiveFilter = (directive) =>
+    !isSpecifiedDirective(directive) && (!filters?.isEnvironmentDefinedDirective?.(directive) ?? true)
+  const typeFilter: TypeFilter = (type) =>
+    !isSpecifiedScalarType(type) &&
+    !isIntrospectionType(type) &&
+    (!filters?.isEnvironmentDefinedType?.(type) ?? true)
+  return printFilteredSchemaWithDirectives(schema, directiveFilter, typeFilter)
 }
 
 function printFilteredSchemaWithDirectives(
   schema: GraphQLSchema,
-  directiveFilter: (type: GraphQLDirective) => boolean,
-  typeFilter: (type: GraphQLNamedType) => boolean
+  directiveFilter: DirectiveFilter,
+  typeFilter: TypeFilter
 ): string {
   const directives = schema.getDirectives().filter(directiveFilter)
   const types = Object.values(schema.getTypeMap()).filter(typeFilter)

src/typegenMetadata.ts

@@ -119,7 +119,7 @@ export class TypegenMetadata {
   generateSchemaFile(schema: GraphQLSchema): string {
     let printedSchema = this.config.customPrintSchemaFn
       ? this.config.customPrintSchemaFn(schema)
-      : printSchemaWithDirectives(schema)
+      : printSchemaWithDirectives(schema, this.config.filters)
     return [SDL_HEADER, printedSchema].join('\n\n')
   }
 

tests/__snapshots__/makeSchema.spec.ts.snap

@@ -8,6 +8,39 @@ type Query {
 }"
 `;
 
+exports[`makeSchema filters can specify custom filters for directives 1`] = `
+"### This file was generated by Nexus Schema
+### Do not make changes to this file directly
+
+
+directive @some_other_directive on OBJECT
+
+type Query {
+  ok: Boolean!
+}
+
+type Random @aws_lambda @some_other_directive {
+  randomId: String!
+}"
+`;
+
+exports[`makeSchema filters can specify custom filters for types 1`] = `
+"### This file was generated by Nexus Schema
+### Do not make changes to this file directly
+
+
+type Query {
+  ok: Boolean!
+}
+
+type Random {
+  expiry: AWSTimestamp
+  expiry2: some_other_scaler
+}
+
+scalar some_other_scaler"
+`;
+
 exports[`makeSchema shouldExitAfterGenerateArtifacts accepts a customPrintSchemaFn 1`] = `
 "### This file was generated by Nexus Schema
 ### Do not make changes to this file directly

tests/makeSchema.spec.ts

@@ -1,9 +1,11 @@
 import { DirectiveLocation, GraphQLDirective, GraphQLInt, GraphQLSchema, printSchema } from 'graphql'
 import os from 'os'
 import path from 'path'
-import { objectType } from '../src'
+import { directive, objectType, scalarType } from '../src'
 import { generateSchema, makeSchema } from '../src/makeSchema'
 import { queryField } from '../src/definitions/queryField'
+import { readFile } from 'fs'
+import { promisify } from 'util'
 
 export type Test = {
   id: string
@@ -184,4 +186,78 @@ describe('makeSchema', () => {
       expect(printSchema(schema).trim()).toMatchSnapshot()
     })
   })
+
+  describe('filters', () => {
+    it('can specify custom filters for directives', async () => {
+      const pathToSchema = path.join(os.tmpdir(), '/schema1.graphql')
+
+      const awsLambdaDirective = directive({
+        name: 'aws_lambda',
+        locations: ['OBJECT'],
+      })
+
+      const someOtherDirective = directive({
+        name: 'some_other_directive',
+        locations: ['OBJECT'],
+      })
+
+      const random = objectType({
+        name: 'Random',
+        directives: [awsLambdaDirective, someOtherDirective],
+        definition(t) {
+          t.nonNull.string('randomId')
+        },
+      })
+
+      await makeSchema({
+        types: [random],
+        filters: {
+          isEnvironmentDefinedDirective: (directive) => {
+            return directive.name === 'aws_lambda'
+          },
+        },
+        outputs: {
+          schema: pathToSchema,
+        },
+      })
+
+      const graphql = await promisify(readFile)(pathToSchema, 'utf-8')
+      expect(graphql.trim()).toMatchSnapshot()
+    })
+
+    it('can specify custom filters for types', async () => {
+      const pathToSchema = path.join(os.tmpdir(), '/schema2.graphql')
+
+      const awsTimestampScaler = scalarType({
+        name: 'AWSTimestamp',
+      })
+
+      const someOtherScaler = scalarType({
+        name: 'some_other_scaler',
+      })
+
+      const random = objectType({
+        name: 'Random',
+        definition(t) {
+          t.field('expiry', { type: awsTimestampScaler })
+          t.field('expiry2', { type: someOtherScaler })
+        },
+      })
+
+      await makeSchema({
+        types: [random],
+        filters: {
+          isEnvironmentDefinedType: (type) => {
+            return type.name === 'AWSTimestamp'
+          },
+        },
+        outputs: {
+          schema: pathToSchema,
+        },
+      })
+
+      const graphql = await promisify(readFile)(pathToSchema, 'utf-8')
+      expect(graphql.trim()).toMatchSnapshot()
+    })
+  })
 })