Introduce mergeSchemas

src/epoxy/index.ts

@@ -1,2 +1,3 @@
-export { mergeGraphQLSchemas } from './schema-mergers/merge-schema';
+export { mergeTypeDefs } from './typedefs-mergers/merge-typedefs';
 export { mergeResolvers } from './resolvers-mergers/merge-resolvers';
+export { mergeSchemas } from './merge-schemas';

src/epoxy/merge-schemas.ts

@@ -0,0 +1,32 @@
+import { GraphQLSchema, DocumentNode } from "graphql";
+import { IResolvers, SchemaDirectiveVisitor, makeExecutableSchema, IResolverValidationOptions } from "graphql-tools";
+import { mergeTypeDefs } from "./typedefs-mergers/merge-typedefs";
+import { asArray } from "../utils/helpers";
+import { mergeResolvers } from "./resolvers-mergers/merge-resolvers";
+import { extractResolversFromSchema } from "../utils";
+
+export interface MergeSchemasConfig {
+    schemas: GraphQLSchema[];
+    typeDefs?: (DocumentNode | string)[] | DocumentNode | string;
+    resolvers?: IResolvers | IResolvers[];
+    schemaDirectives ?: { [directiveName: string] : typeof SchemaDirectiveVisitor };
+    resolverValidationOptions ?: IResolverValidationOptions;
+}
+
+export function mergeSchemas(config: MergeSchemasConfig) {
+    const typeDefs = mergeTypeDefs([
+        ...config.schemas,
+        ...config.typeDefs ? asArray(config.typeDefs) : []
+    ]);
+    const resolvers = mergeResolvers([
+        ...config.schemas.map(schema => extractResolversFromSchema(schema)),
+        ...config.resolvers ? asArray<IResolvers>(config.resolvers) : []
+    ]);
+
+    return makeExecutableSchema({
+        typeDefs,
+        resolvers,
+        schemaDirectives: config.schemaDirectives,
+        resolverValidationOptions: config.resolverValidationOptions
+    })
+}

src/epoxy/typedefs-mergers/directives.ts

@@ -0,0 +1,79 @@
+import { ArgumentNode, DirectiveNode } from 'graphql/language/ast';
+import { DirectiveDefinitionNode, ListValueNode, NameNode, print } from 'graphql';
+
+function directiveAlreadyExists(directivesArr: ReadonlyArray<DirectiveNode>, otherDirective: DirectiveNode): boolean {
+  return !!directivesArr.find(directive => directive.name.value === otherDirective.name.value);
+}
+
+function nameAlreadyExists(name: NameNode, namesArr: ReadonlyArray<NameNode>): boolean {
+  return namesArr.some(({ value }) => value === name.value);
+}
+
+function mergeArguments(a1: ArgumentNode[], a2: ArgumentNode[]): ArgumentNode[] {
+  const result: ArgumentNode[] = [...a2];
+
+  for (const argument of a1) {
+    const existingIndex = result.findIndex(a => a.name.value === argument.name.value);
+
+    if (existingIndex > -1) {
+      const existingArg = result[existingIndex];
+
+      if (existingArg.value.kind === 'ListValue') {
+        (existingArg.value as any).values = [
+          ...existingArg.value.values,
+          ...(argument.value as ListValueNode).values,
+        ];
+      } else {
+        (existingArg as any).value = argument.value;
+      }
+    } else {
+      result.push(argument);
+    }
+  }
+
+  return result;
+}
+
+export function mergeDirectives(d1: ReadonlyArray<DirectiveNode>, d2: ReadonlyArray<DirectiveNode>): DirectiveNode[] {
+  const result = [...d2];
+
+  for (const directive of d1) {
+    if (directiveAlreadyExists(result, directive)) {
+      const existingDirectiveIndex = result.findIndex(d => d.name.value === directive.name.value);
+      const existingDirective = result[existingDirectiveIndex];
+      (result[existingDirectiveIndex] as any).arguments = mergeArguments(existingDirective.arguments as any, directive.arguments as any);
+    } else {
+      result.push(directive);
+    }
+  }
+
+  return result;
+}
+
+function validateInputs(node: DirectiveDefinitionNode, existingNode: DirectiveDefinitionNode): void | never {
+  const printedNode = print(node);
+  const printedExistingNode = print(existingNode);
+  const leaveInputs = new RegExp('(directive @\w*\d*)|( on .*$)', 'g');
+  const sameArguments = printedNode.replace(leaveInputs, '') === printedExistingNode.replace(leaveInputs, '');
+
+  if (!sameArguments) {
+    throw new Error(`Unable to merge GraphQL directive "${node.name.value}". \nExisting directive:  \n\t${printedExistingNode} \nReceived directive: \n\t${printedNode}`);
+  }
+}
+
+export function mergeDirective(node: DirectiveDefinitionNode, existingNode?: DirectiveDefinitionNode): DirectiveDefinitionNode {
+  if (existingNode) {
+
+    validateInputs(node, existingNode);
+
+    return {
+      ...node,
+      locations: [
+        ...existingNode.locations,
+        ...(node.locations.filter(name => !nameAlreadyExists(name, existingNode.locations))),
+      ],
+    };
+  }
+
+  return node;
+}

src/epoxy/typedefs-mergers/enum-values.ts

@@ -0,0 +1,12 @@
+import { EnumValueDefinitionNode } from 'graphql/language/ast';
+
+function alreadyExists(arr: ReadonlyArray<EnumValueDefinitionNode>, other: EnumValueDefinitionNode): boolean {
+  return !!arr.find(v => v.name.value === other.name.value);
+}
+
+export function mergeEnumValues(first: ReadonlyArray<EnumValueDefinitionNode>, second: ReadonlyArray<EnumValueDefinitionNode>): EnumValueDefinitionNode[] {
+  return [
+    ...second,
+    ...(first.filter(d => !alreadyExists(second, d))),
+  ];
+}

src/epoxy/typedefs-mergers/enum.ts

@@ -0,0 +1,20 @@
+import { EnumTypeDefinitionNode, EnumTypeExtensionNode } from 'graphql';
+import { mergeDirectives } from './directives';
+import { mergeEnumValues } from './enum-values';
+
+export function mergeEnum(e1: EnumTypeDefinitionNode | EnumTypeExtensionNode, e2: EnumTypeDefinitionNode | EnumTypeExtensionNode): EnumTypeDefinitionNode | EnumTypeExtensionNode {
+
+  if (e2) {
+    return {
+      name: e1.name,
+      description: e1['description'] || e2['description'],
+      kind: (e1.kind === 'EnumTypeDefinition' || e2.kind === 'EnumTypeDefinition') ? 'EnumTypeDefinition' : 'EnumTypeExtension',
+      loc: e1.loc,
+      directives: mergeDirectives(e1.directives, e2.directives),
+      values: mergeEnumValues(e1.values, e2.values),
+    } as any;
+  }
+
+  return e1;
+
+}

src/epoxy/typedefs-mergers/fields.ts

@@ -0,0 +1,33 @@
+import { FieldDefinitionNode } from 'graphql/language/ast';
+import { extractType } from './utils';
+import { mergeDirectives } from './directives';
+
+function fieldAlreadyExists(fieldsArr: ReadonlyArray<any>, otherField: any): boolean {
+  const result: FieldDefinitionNode | null = fieldsArr.find(field => field.name.value === otherField.name.value);
+
+  if (result) {
+    const t1 = extractType(result.type);
+    const t2 = extractType(otherField.type);
+
+    if (t1.name.value !== t2.name.value) {
+      throw new Error(`Field "${otherField.name.value}" already defined with a different type. Declared as "${t1.name.value}", but you tried to override with "${t2.name.value}"`);
+    }
+  }
+
+  return !!result;
+}
+
+export function mergeFields<T>(f1: ReadonlyArray<T>, f2: ReadonlyArray<T>): T[] {
+  const result: T[] = [...f2];
+
+  for (const field of f1) {
+    if (fieldAlreadyExists(result, field)) {
+      const existing = result.find((f: any) => f.name.value === (field as any).name.value);
+      existing['directives'] = mergeDirectives(field['directives'], existing['directives']);
+    } else {
+      result.push(field);
+    }
+  }
+
+  return result;
+}

src/epoxy/typedefs-mergers/input-type.ts

@@ -0,0 +1,26 @@
+import { InputObjectTypeDefinitionNode } from 'graphql';
+import { mergeFields } from './fields';
+import { mergeDirectives } from './directives';
+import { InputValueDefinitionNode, InputObjectTypeExtensionNode } from 'graphql/language/ast';
+
+export function mergeInputType(
+  node: InputObjectTypeDefinitionNode | InputObjectTypeExtensionNode,
+  existingNode: InputObjectTypeDefinitionNode | InputObjectTypeExtensionNode): InputObjectTypeDefinitionNode | InputObjectTypeExtensionNode {
+
+  if (existingNode) {
+    try {
+      return {
+        name: node.name,
+        description: node['description'] || existingNode['description'],
+        kind: (node.kind === 'InputObjectTypeDefinition' || existingNode.kind === 'InputObjectTypeDefinition') ? 'InputObjectTypeDefinition' : 'InputObjectTypeExtension',
+        loc: node.loc,
+        fields: mergeFields<InputValueDefinitionNode>(node.fields, existingNode.fields),
+        directives: mergeDirectives(node.directives, existingNode.directives),
+      } as any;
+    } catch (e) {
+      throw new Error(`Unable to merge GraphQL input type "${node.name.value}": ${e.message}`);
+    }
+  }
+
+  return node;
+}

src/epoxy/typedefs-mergers/interface.ts

@@ -0,0 +1,25 @@
+import { InterfaceTypeDefinitionNode, InterfaceTypeExtensionNode } from 'graphql';
+import { mergeFields } from './fields';
+import { mergeDirectives } from './directives';
+
+export function mergeInterface(
+  node: InterfaceTypeDefinitionNode | InterfaceTypeExtensionNode,
+  existingNode: InterfaceTypeDefinitionNode | InterfaceTypeExtensionNode): InterfaceTypeDefinitionNode | InterfaceTypeExtensionNode {
+
+  if (existingNode) {
+    try {
+      return {
+        name: node.name,
+        description: node['description'] || existingNode['description'],
+        kind: (node.kind === 'InterfaceTypeDefinition' || existingNode.kind === 'InterfaceTypeDefinition') ? 'InterfaceTypeDefinition' : 'InterfaceTypeExtension',
+        loc: node.loc,
+        fields: mergeFields(node.fields, existingNode.fields),
+        directives: mergeDirectives(node.directives, existingNode.directives),
+      } as any;
+    } catch (e) {
+      throw new Error(`Unable to merge GraphQL interface "${node.name.value}": ${e.message}`);
+    }
+  }
+
+  return node;
+}

src/epoxy/typedefs-mergers/merge-named-type-array.ts

@@ -0,0 +1,12 @@
+import { NamedTypeNode } from 'graphql/language/ast';
+
+function alreadyExists(arr: ReadonlyArray<NamedTypeNode>, other: NamedTypeNode): boolean {
+  return !!arr.find(i => i.name.value === other.name.value);
+}
+
+export function mergeNamedTypeArray(first: ReadonlyArray<NamedTypeNode>, second: ReadonlyArray<NamedTypeNode>): NamedTypeNode[] {
+  return [
+    ...second,
+    ...(first.filter(d => !alreadyExists(second, d))),
+  ];
+}

src/epoxy/typedefs-mergers/merge-nodes.ts

@@ -0,0 +1,52 @@
+import { DefinitionNode } from 'graphql';
+import {
+  isGraphQLEnum,
+  isGraphQLInputType,
+  isGraphQLInterface,
+  isGraphQLScalar,
+  isGraphQLType,
+  isGraphQLUnion,
+  isGraphQLDirective,
+  isGraphQLTypeExtension,
+  isGraphQLInputTypeExtension,
+  isGraphQLEnumExtension,
+  isGraphQLUnionExtension,
+  isGraphQLScalarExtension,
+  isGraphQLInterfaceExtension,
+} from './utils';
+import { mergeType } from './type';
+import { mergeEnum } from './enum';
+import { mergeUnion } from './union';
+import { mergeInputType } from './input-type';
+import { mergeInterface } from './interface';
+import { mergeDirective } from './directives';
+
+export type MergedResultMap = {[name: string]: DefinitionNode};
+
+export function mergeGraphQLNodes(nodes: ReadonlyArray<DefinitionNode>): MergedResultMap {
+  return nodes.reduce<MergedResultMap>((prev: MergedResultMap, nodeDefinition: DefinitionNode) => {
+    const node = (nodeDefinition as any);
+
+    if (node && node.name && node.name.value) {
+      const name = node.name.value;
+
+      if (isGraphQLType(nodeDefinition) || isGraphQLTypeExtension(nodeDefinition)) {
+        prev[name] = mergeType(nodeDefinition, prev[name] as any);
+      } else if (isGraphQLEnum(nodeDefinition) || isGraphQLEnumExtension(nodeDefinition)) {
+        prev[name] = mergeEnum(nodeDefinition, prev[name] as any);
+      } else if (isGraphQLUnion(nodeDefinition) || isGraphQLUnionExtension(nodeDefinition)) {
+        prev[name] = mergeUnion(nodeDefinition, prev[name] as any);
+      } else if (isGraphQLScalar(nodeDefinition) || isGraphQLScalarExtension(nodeDefinition)) {
+        prev[name] = nodeDefinition;
+      } else if (isGraphQLInputType(nodeDefinition) || isGraphQLInputTypeExtension(nodeDefinition)) {
+        prev[name] = mergeInputType(nodeDefinition, prev[name] as any);
+      } else if (isGraphQLInterface(nodeDefinition) || isGraphQLInterfaceExtension(nodeDefinition)) {
+        prev[name] = mergeInterface(nodeDefinition, prev[name] as any);
+      } else if (isGraphQLDirective(nodeDefinition)) {
+        prev[name] = mergeDirective(nodeDefinition, prev[name] as any);
+      }
+    }
+
+    return prev;
+  }, {});
+}

src/epoxy/schema-mergers/merge-schema.ts → src/epoxy/typedefs-mergers/merge-typedefs.ts

@@ -22,7 +22,7 @@ interface Config {
   useSchemaDefinition?: boolean;
 }
 
-export function mergeGraphQLSchemas(types: Array<string | Source | DocumentNode | GraphQLSchema>, config?: Partial<Config>): DocumentNode {
+export function mergeTypeDefs(types: Array<string | Source | DocumentNode | GraphQLSchema>, config?: Partial<Config>): DocumentNode {
   return {
     kind: 'Document',
     definitions: mergeGraphQLTypes(types, {

src/epoxy/typedefs-mergers/type.ts

@@ -0,0 +1,24 @@
+import { ObjectTypeDefinitionNode, ObjectTypeExtensionNode } from 'graphql';
+import { mergeFields } from './fields';
+import { mergeDirectives } from './directives';
+import { mergeNamedTypeArray } from './merge-named-type-array';
+
+export function mergeType(node: ObjectTypeDefinitionNode | ObjectTypeExtensionNode, existingNode: ObjectTypeDefinitionNode | ObjectTypeExtensionNode): ObjectTypeDefinitionNode | ObjectTypeExtensionNode {
+  if (existingNode) {
+    try {
+      return {
+        name: node.name,
+        description: node['description'] || existingNode['description'],
+        kind: (node.kind === 'ObjectTypeDefinition' || existingNode.kind === 'ObjectTypeDefinition') ? 'ObjectTypeDefinition' : 'ObjectTypeExtension',
+        loc: node.loc,
+        fields: mergeFields(node.fields, existingNode.fields),
+        directives: mergeDirectives(node.directives, existingNode.directives),
+        interfaces: mergeNamedTypeArray(node.interfaces, existingNode.interfaces),
+      } as any;
+    } catch (e) {
+      throw new Error(`Unable to merge GraphQL type "${node.name.value}": ${e.message}`);
+    }
+  }
+
+  return node;
+}

src/epoxy/typedefs-mergers/union.ts

@@ -0,0 +1,22 @@
+import { UnionTypeDefinitionNode, UnionTypeExtensionNode } from 'graphql';
+import { mergeDirectives } from './directives';
+import { mergeNamedTypeArray } from './merge-named-type-array';
+
+export function mergeUnion(first: UnionTypeDefinitionNode | UnionTypeExtensionNode, second: UnionTypeDefinitionNode | UnionTypeExtensionNode): UnionTypeDefinitionNode | UnionTypeExtensionNode {
+  if (second) {
+    return {
+      name: first.name,
+      description: first['description'] || second['description'],
+      directives: mergeDirectives(first.directives, second.directives),
+      kind: (first.kind === 'UnionTypeDefinition' || second.kind === 'UnionTypeDefinition') ? 'UnionTypeDefinition' : 'UnionTypeExtension',
+      loc: first.loc,
+      types: mergeNamedTypeArray(first.types, second.types),
+    } as any;
+  }
+
+  if (first.kind === 'UnionTypeExtension') {
+    throw new Error(`Unable to extend undefined GraphQL union: ${first.name}`);
+  }
+
+  return first;
+}