Interface and union resolvers

packages/graphqlgen/benchmarks/micro/index.ts

@@ -3,6 +3,7 @@ import * as Benchmark from '../lib/benchmark'
 
 const type = {
   name: 'Z',
+  implements: null,
   type: {
     name: 'Z',
     isInput: false,
@@ -18,6 +19,7 @@ const type = {
 const typeMap: Core.InputTypesMap = {
   A: {
     name: 'A',
+    implements: null,
     type: {
       name: 'A',
       isInput: true,
@@ -41,6 +43,7 @@ const typeMap: Core.InputTypesMap = {
           isUnion: false,
           isRequired: false,
           isArray: false,
+          isArrayRequired: false,
         },
       },
       {
@@ -56,12 +59,14 @@ const typeMap: Core.InputTypesMap = {
           isUnion: false,
           isRequired: false,
           isArray: false,
+          isArrayRequired: false,
         },
       },
     ],
   },
   B: {
     name: 'B',
+    implements: null,
     type: {
       name: 'B',
       isInput: true,
@@ -85,12 +90,14 @@ const typeMap: Core.InputTypesMap = {
           isUnion: false,
           isRequired: false,
           isArray: false,
+          isArrayRequired: false,
         },
       },
     ],
   },
   C: {
     name: 'C',
+    implements: null,
     type: {
       name: 'C',
       isInput: true,
@@ -114,12 +121,14 @@ const typeMap: Core.InputTypesMap = {
           isUnion: false,
           isRequired: false,
           isArray: false,
+          isArrayRequired: false,
         },
       },
     ],
   },
   D: {
     name: 'D',
+    implements: null,
     type: {
       name: 'D',
       isInput: true,
@@ -143,6 +152,7 @@ const typeMap: Core.InputTypesMap = {
           isUnion: false,
           isRequired: false,
           isArray: false,
+          isArrayRequired: false,
         },
       },
     ],

packages/graphqlgen/package.json

@@ -20,6 +20,7 @@
     "watch": "tsc -w",
     "lint": "tslint --project tsconfig.json {src,test}/**/*.ts",
     "test": "jest",
+    "check:types": "yarn tsc --noEmit",
     "test:watch": "jest --watch",
     "test:ci": "npm run lint && jest --maxWorkers 4",
     "gen": "ts-node --files src/index.ts"

packages/graphqlgen/src/generators/common.spec.ts

@@ -1,7 +1,8 @@
+import * as Source from '../source-helper'
 import * as Common from './common'
 
 it('getDistinctInputTypes', () => {
-  const Z = {
+  const Z: Source.GraphQLTypeObject = {
     name: 'Z',
     type: {
       name: 'Z',
@@ -13,11 +14,13 @@ it('getDistinctInputTypes', () => {
       isUnion: false,
     },
     fields: [],
+    implements: null,
   }
 
   const typeMap: Common.InputTypesMap = {
     A: {
       name: 'A',
+      implements: null,
       type: {
         name: 'A',
         isInput: true,
@@ -64,6 +67,7 @@ it('getDistinctInputTypes', () => {
     },
     B: {
       name: 'B',
+      implements: null,
       type: {
         name: 'B',
         isInput: true,
@@ -94,6 +98,7 @@ it('getDistinctInputTypes', () => {
     },
     C: {
       name: 'C',
+      implements: null,
       type: {
         name: 'C',
         isInput: true,
@@ -124,6 +129,7 @@ it('getDistinctInputTypes', () => {
     },
     D: {
       name: 'D',
+      implements: null,
       type: {
         name: 'D',
         isInput: true,

packages/graphqlgen/src/generators/common.ts

@@ -2,9 +2,11 @@ import * as os from 'os'
 
 import {
   GraphQLTypeObject,
-  GraphQLType,
+  GraphQLTypeDefinition,
   GraphQLTypeField,
   getGraphQLEnumValues,
+  GraphQLInterfaceObject,
+  GraphQLUnionObject,
 } from '../source-helper'
 import { ModelMap, ContextDefinition, GenerateArgs, Model } from '../types'
 import {
@@ -28,6 +30,24 @@ export interface TypeToInputTypeAssociation {
   [objectTypeName: string]: string[]
 }
 
+export type InterfacesMap = Record<string, GraphQLTypeDefinition[]>
+
+export const createInterfacesMap = (
+  interfaces: GraphQLInterfaceObject[],
+): InterfacesMap =>
+  interfaces.reduce<InterfacesMap>((interfacesMap, inter) => {
+    interfacesMap[inter.name] = inter.implementors
+    return interfacesMap
+  }, {})
+
+export type UnionsMap = Record<string, GraphQLTypeDefinition[]>
+
+export const createUnionsMap = (unions: GraphQLUnionObject[]): UnionsMap =>
+  unions.reduce<UnionsMap>((unionsMap, union) => {
+    unionsMap[union.name] = union.types
+    return unionsMap
+  }, {})
+
 export function fieldsFromModelDefinition(
   modelDef: TypeDefinition,
 ): FieldDefinition[] {
@@ -114,7 +134,7 @@ export function getContextName(context?: ContextDefinition) {
 }
 
 export function getModelName(
-  type: GraphQLType,
+  type: GraphQLTypeDefinition,
   modelMap: ModelMap,
   emptyType: string = '{}',
 ): string {
@@ -199,21 +219,63 @@ const kv = (
   return `${key}${isOptional ? '?' : ''}: ${value}`
 }
 
-const array = (innerType: string, config: { innerUnion?: boolean } = {}) => {
+const array = (
+  innerType: string,
+  config: { innerUnion?: boolean } = {},
+): string => {
   return config.innerUnion ? `${innerType}[]` : `Array<${innerType}>`
 }
 
+const union = (types: string[]): string => {
+  return types.join(' | ')
+}
+
 type FieldPrintOptions = {
   isReturn?: boolean
 }
 
 export const printFieldLikeType = (
   field: GraphQLTypeField,
   modelMap: ModelMap,
+  interfacesMap: InterfacesMap,
+  unionsMap: UnionsMap,
   options: FieldPrintOptions = {
     isReturn: false,
   },
 ): string => {
+  if (field.type.isInterface || field.type.isUnion) {
+    const typesMap = field.type.isInterface ? interfacesMap : unionsMap
+
+    const modelNames = typesMap[field.type.name].map(type =>
+      getModelName(type, modelMap),
+    )
+
+    let rendering = union(modelNames)
+
+    if (!field.type.isRequired) {
+      rendering = nullable(rendering)
+    }
+
+    if (field.type.isArray) {
+      rendering = array(rendering, { innerUnion: false })
+    }
+
+    if (!field.type.isArrayRequired) {
+      rendering = nullable(rendering)
+    }
+
+    // We do not have to handle defaults becuase graphql only
+    // supports defaults on field params but conversely
+    // interfaces and unions are only supported on output. Therefore
+    // these two features will never cross.
+
+    // No check for isReturn option because unions and interfaces
+    // cannot be used to type graphql field parameters which implies
+    // this branch will always be for a return case.
+
+    return rendering
+  }
+
   const name = field.type.isScalar
     ? getTypeFromGraphQLType(field.type.name)
     : field.type.isInput || field.type.isEnum
@@ -335,11 +397,13 @@ export function isParentType(name: string) {
 
 export function groupModelsNameByImportPath(models: Model[]) {
   return models.reduce<{ [importPath: string]: string[] }>((acc, model) => {
-    if (acc[model.importPathRelativeToOutput] === undefined) {
-      acc[model.importPathRelativeToOutput] = []
+    const fileModels = acc[model.importPathRelativeToOutput] || []
+
+    if (!fileModels.includes(model.definition.name)) {
+      fileModels.push(model.definition.name)
     }
 
-    acc[model.importPathRelativeToOutput].push(model.definition.name)
+    acc[model.importPathRelativeToOutput] = fileModels
 
     return acc
   }, {})