flow plugin: fixes issues with scalars resolvers and scalars imports

packages/plugins/flow-resolvers/src/index.ts

@@ -1,6 +1,6 @@
 import { ScalarsMap } from 'graphql-codegen-flow';
 import { DocumentFile, GraphQLSchema, PluginFunction } from 'graphql-codegen-core';
-import { parse, printSchema, visit } from 'graphql';
+import { isScalarType, parse, printSchema, visit } from 'graphql';
 import { FlowResolversVisitor } from './visitor';
 
 export interface FlowResolversPluginConfig {
@@ -17,14 +17,16 @@ export const plugin: PluginFunction<FlowResolversPluginConfig> = (
   config: FlowResolversPluginConfig
 ) => {
   const imports = ['GraphQLResolveInfo'];
-  const hasScalars = false;
+  const hasScalars = Object.values(schema.getTypeMap())
+    .filter(t => t.astNode)
+    .some(isScalarType);
 
   if (hasScalars) {
-    imports.push('GraphQLScalarType', 'GraphQLScalarTypeConfig');
+    imports.push('GraphQLScalarTypeConfig');
   }
 
   const result = `
-import { ${imports.join(', ')} } from 'graphql';
+import { ${imports.join(', ')} } from 'graphql/type';
 
 export type Resolver<Result, Parent = {}, Context = {}, Args = {}> = (
   parent?: Parent,

packages/plugins/flow-resolvers/src/visitor.ts

@@ -136,7 +136,7 @@ export class FlowResolversVisitor implements BasicFlowVisitor {
 
     return new DeclarationBlock()
       .export()
-      .asKind('type')
+      .asKind('interface')
       .withName(this.convertName(node.name + 'ScalarConfig'), ` extends GraphQLScalarTypeConfig<${baseName}, any>`)
       .withBlock(indent(`name: '${node.name}'`)).string;
   };

packages/plugins/flow-resolvers/tests/flow-resolvers.spec.ts

@@ -1,9 +1,7 @@
 import 'graphql-codegen-core/dist/testing';
-import { FlowResolversVisitor } from '../src/visitor';
-import { parse, visit, printSchema } from 'graphql';
-import { validateFlow } from './validate-flow';
 import { makeExecutableSchema } from 'graphql-tools';
 import { plugin } from '../src';
+import { typeDefs } from '../../../graphql-codegen-cli/tests/test-files/schema-dir/schema';
 
 describe('Flow Resolvers Plugin', () => {
   const schema = makeExecutableSchema({
@@ -53,9 +51,9 @@ describe('Flow Resolvers Plugin', () => {
       bar?: Resolver<string, ParentType, Context>,
     }
 
-    export type MyScalarScalarConfig extends GraphQLScalarTypeConfig<MyScalar, any> = {
+    export interface MyScalarScalarConfig extends GraphQLScalarTypeConfig<MyScalar, any> {
       name: 'MyScalar'
-    };
+    }
 
     export interface MyTypeResolvers<Context = any, ParentType = MyType> {
       foo?: Resolver<string, ParentType, Context>,
@@ -84,6 +82,21 @@ describe('Flow Resolvers Plugin', () => {
     }
     `);
   });
+
+  it('Should generate the correct imports when schema has scalars', () => {
+    const result = plugin(makeExecutableSchema({ typeDefs: `scalar MyScalar` }), [], {}, { outputFile: '' });
+
+    expect(result).toBeSimilarStringTo(`import { GraphQLResolveInfo, GraphQLScalarTypeConfig } from 'graphql/type';`);
+  });
+
+  it('Should generate the correct imports when schema has no scalars', () => {
+    const result = plugin(makeExecutableSchema({ typeDefs: `type MyType { f: String }` }), [], {}, { outputFile: '' });
+
+    expect(result).not.toBeSimilarStringTo(
+      `import { GraphQLResolveInfo, GraphQLScalarTypeConfig } from 'graphql/type';`
+    );
+  });
+
   it('Should generate basic type resolvers with mapping', () => {
     const result = plugin(
       schema,
@@ -104,9 +117,9 @@ describe('Flow Resolvers Plugin', () => {
       bar?: Resolver<string, ParentType, Context>,
     }
 
-    export type MyScalarScalarConfig extends GraphQLScalarTypeConfig<MyScalar, any> = {
+    export interface MyScalarScalarConfig extends GraphQLScalarTypeConfig<MyScalar, any> {
       name: 'MyScalar'
-    };
+    }
 
     export interface MyTypeResolvers<Context = any, ParentType = MyType> {
       foo?: Resolver<string, ParentType, Context>,