From daed81bf820a5acb976cf0a1ad1e9fc4f2407c8c Mon Sep 17 00:00:00 2001
From: Daniel Rearden <danielrearden@gmail.com>
Date: Thu, 23 Apr 2020 05:00:23 -0400
Subject: [PATCH] Fix visitEnumValue to allow modifying the enum value (#1391)

---
 CHANGELOG.md                |  3 +++
 src/test/directives.test.ts | 35 +++++++++++++++++++++++++++++++++++
 src/utils/visitSchema.ts    | 37 +++++++++++++++++++++++++++++++++----
 3 files changed, 71 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b1fdec3be07..04bf1077700 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,9 @@
 
 ### Next
 
+- Fix visitEnumValue to allow modifying the enum value  <br/>
+  [@danielrearden](https://github.com/danielrearden) in [#1003](https://github.com/ardatan/graphql-tools/pull/1391)
+
 ### 5.0.0
 
 That is a major release where we went through all issues and PRs and got the library back into great shape.
diff --git a/src/test/directives.test.ts b/src/test/directives.test.ts
index e4010618f16..9cd4e6d39e2 100644
--- a/src/test/directives.test.ts
+++ b/src/test/directives.test.ts
@@ -1358,6 +1358,41 @@ describe('@directives', () => {
     ]);
   });
 
+  test("can modify enum value's value", () => {
+    const schema = makeExecutableSchema({
+      typeDefs: `
+      directive @value(new: String!) on ENUM_VALUE
+
+      type Query {
+        device: Device
+      }
+
+      enum Device {
+        PHONE
+        TABLET
+        LAPTOP @value(new: "COMPUTER")
+      }`,
+
+      schemaDirectives: {
+        value: class extends SchemaDirectiveVisitor {
+          public visitEnumValue(value: GraphQLEnumValue): GraphQLEnumValue {
+            return {
+              ...value,
+              value: this.args.new,
+            };
+          }
+        },
+      },
+    });
+
+    const Device = schema.getType('Device') as GraphQLEnumType;
+    expect(Device.getValues().map((value) => value.value)).toEqual([
+      'PHONE',
+      'TABLET',
+      'COMPUTER',
+    ]);
+  });
+
   test('can swap names of GraphQLNamedType objects', () => {
     const schema = makeExecutableSchema({
       typeDefs: `
diff --git a/src/utils/visitSchema.ts b/src/utils/visitSchema.ts
index 282bc684aa0..ffb219eb839 100644
--- a/src/utils/visitSchema.ts
+++ b/src/utils/visitSchema.ts
@@ -14,6 +14,8 @@ import {
   isUnionType,
   isEnumType,
   isInputType,
+  GraphQLEnumValue,
+  GraphQLEnumType,
 } from 'graphql';
 
 import {
@@ -24,6 +26,7 @@ import {
   SchemaVisitorMap,
 } from '../Interfaces';
 import updateEachKey from '../esUtils/updateEachKey';
+import keyValMap from '../esUtils/keyValMap';
 
 import { healSchema } from './heal';
 import { SchemaVisitor } from './SchemaVisitor';
@@ -193,14 +196,40 @@ export function visitSchema(
     }
 
     if (isEnumType(type)) {
-      const newEnum = callMethod('visitEnum', type);
+      let newEnum = callMethod('visitEnum', type);
 
       if (newEnum != null) {
-        updateEachKey(newEnum.getValues(), (value) =>
-          callMethod('visitEnumValue', value, {
+        const newValues: Array<GraphQLEnumValue> = [];
+
+        updateEachKey(newEnum.getValues(), (value) => {
+          const newValue = callMethod('visitEnumValue', value, {
             enumType: newEnum,
-          }),
+          });
+          // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+          if (newValue) {
+            newValues.push(newValue);
+          }
+        });
+
+        // Recreate the enum type if any of the values changed
+        const valuesUpdated = newValues.some(
+          (value, index) => value !== newEnum.getValues()[index],
         );
+        if (valuesUpdated) {
+          newEnum = new GraphQLEnumType({
+            ...(newEnum as GraphQLEnumType).toConfig(),
+            values: keyValMap(
+              newValues,
+              (value) => value.name,
+              (value) => ({
+                value: value.value,
+                deprecationReason: value.deprecationReason,
+                description: value.description,
+                astNode: value.astNode,
+              }),
+            ),
+          }) as GraphQLEnumType & T;
+        }
       }
 
       return newEnum;