fix directive and update sample

Author: KaiyueGuan

examples/federation/reviews-service/index.js

@@ -5,6 +5,7 @@ const GraphQLComponent = require('../../../lib');
 const ReviewsDataSource = require('./datasource');
 const resolvers = require('./resolvers');
 const types = require('./types');
+const toUppercaseDirective = require('./toUppercaseDirective')
 
 class ReviewsComponent extends GraphQLComponent {
   constructor(options) {
@@ -17,6 +18,9 @@ const run = async function () {
     types,
     resolvers,
     dataSources: [new ReviewsDataSource()],
+    directives: {
+      toUppercase: toUppercaseDirective
+    },
     federation: true
   });
 

examples/federation/reviews-service/schema.graphql

@@ -1,6 +1,8 @@
+directive @toUppercase on FIELD_DEFINITION
+
 type Review {
   id: ID!
-  content: String!
+  content: String! @toUppercase
 }
 
 extend type Property @key(fields: "id") {

examples/federation/reviews-service/toUppercaseDirective.js

@@ -0,0 +1,25 @@
+const {getDirective, MapperKind, mapSchema} = require("@graphql-tools/utils");
+const {defaultFieldResolver} = require("graphql");
+
+function toUppercaseDirective(directiveName) {
+    return (schema) => mapSchema(schema, {
+        [MapperKind.OBJECT_FIELD]: (fieldConfig) => {
+            const upperDirective = getDirective(schema, fieldConfig, directiveName)?.[0];
+            if (upperDirective) {
+                const {resolve = defaultFieldResolver} = fieldConfig;
+                return {
+                    ...fieldConfig,
+                    resolve: async function (source, args, context, info) {
+                        const result = await resolve(source, args, context, info);
+                        if (typeof result === 'string') {
+                            return result.toUpperCase();
+                        }
+                        return result;
+                    }
+                }
+            }
+        }
+    })
+}
+
+module.exports = toUppercaseDirective

lib/index.js

@@ -102,11 +102,13 @@ class GraphQLComponent {
   _getMakeSchemaFunction() {
     if (this._federation) {
       return (schemaConfig) => {
-        const schema = buildFederatedSchema(schemaConfig);
+        let schema = buildFederatedSchema(schemaConfig);
 
         // allows a federated schema to have custom directives using the old class based directive implementation
         if (this._directives) {
-          SchemaDirectiveVisitor.visitSchemaDirectives(schema, this._directives);
+          for (const name in this._directives) {
+            schema = this._directives[name](name)(schema)
+          }
         }
 
         return schema;