From 94ec0820a1e11abc0f6a2937bcde47afdc1259b1 Mon Sep 17 00:00:00 2001
From: Ivan Goncharov <ivan.goncharov.ua@gmail.com>
Date: Tue, 10 May 2022 13:48:07 +0300
Subject: [PATCH] validateSchema: unify check of root types

---
 src/jsutils/__tests__/capitalize-test.ts | 21 ++++++++++++
 src/jsutils/capitalize.ts                |  6 ++++
 src/type/validate.ts                     | 43 +++++++++---------------
 3 files changed, 43 insertions(+), 27 deletions(-)
 create mode 100644 src/jsutils/__tests__/capitalize-test.ts
 create mode 100644 src/jsutils/capitalize.ts

diff --git a/src/jsutils/__tests__/capitalize-test.ts b/src/jsutils/__tests__/capitalize-test.ts
new file mode 100644
index 0000000000..48ae886c11
--- /dev/null
+++ b/src/jsutils/__tests__/capitalize-test.ts
@@ -0,0 +1,21 @@
+import { expect } from 'chai';
+import { describe, it } from 'mocha';
+
+import { capitalize } from '../capitalize';
+
+describe('capitalize', () => {
+  it('Converts the first character of string to upper case and the remaining to lower case', () => {
+    expect(capitalize('')).to.equal('');
+
+    expect(capitalize('a')).to.equal('A');
+    expect(capitalize('A')).to.equal('A');
+
+    expect(capitalize('ab')).to.equal('Ab');
+    expect(capitalize('aB')).to.equal('Ab');
+    expect(capitalize('Ab')).to.equal('Ab');
+    expect(capitalize('AB')).to.equal('Ab');
+
+    expect(capitalize('platypus')).to.equal('Platypus');
+    expect(capitalize('PLATYPUS')).to.equal('Platypus');
+  });
+});
diff --git a/src/jsutils/capitalize.ts b/src/jsutils/capitalize.ts
new file mode 100644
index 0000000000..064dddcf0f
--- /dev/null
+++ b/src/jsutils/capitalize.ts
@@ -0,0 +1,6 @@
+/**
+ * Converts the first character of string to upper case and the remaining to lower case.
+ */
+export function capitalize(str: string): string {
+  return str.charAt(0).toUpperCase() + str.slice(1).toLowerCase();
+}
diff --git a/src/type/validate.ts b/src/type/validate.ts
index 126e97d980..9ce665435a 100644
--- a/src/type/validate.ts
+++ b/src/type/validate.ts
@@ -1,3 +1,4 @@
+import { capitalize } from '../jsutils/capitalize';
 import { inspect } from '../jsutils/inspect';
 import type { Maybe } from '../jsutils/Maybe';
 
@@ -112,37 +113,25 @@ class SchemaValidationContext {
 
 function validateRootTypes(context: SchemaValidationContext): void {
   const schema = context.schema;
-  const queryType = schema.getQueryType();
-  if (!queryType) {
+
+  if (schema.getQueryType() == null) {
     context.reportError('Query root type must be provided.', schema.astNode);
-  } else if (!isObjectType(queryType)) {
-    context.reportError(
-      `Query root type must be Object type, it cannot be ${inspect(
-        queryType,
-      )}.`,
-      getOperationTypeNode(schema, OperationTypeNode.QUERY) ??
-        (queryType as any).astNode,
-    );
   }
 
-  const mutationType = schema.getMutationType();
-  if (mutationType && !isObjectType(mutationType)) {
-    context.reportError(
-      'Mutation root type must be Object type if provided, it cannot be ' +
-        `${inspect(mutationType)}.`,
-      getOperationTypeNode(schema, OperationTypeNode.MUTATION) ??
-        (mutationType as any).astNode,
-    );
-  }
+  for (const operationType of Object.values(OperationTypeNode)) {
+    const rootType = schema.getRootType(operationType);
 
-  const subscriptionType = schema.getSubscriptionType();
-  if (subscriptionType && !isObjectType(subscriptionType)) {
-    context.reportError(
-      'Subscription root type must be Object type if provided, it cannot be ' +
-        `${inspect(subscriptionType)}.`,
-      getOperationTypeNode(schema, OperationTypeNode.SUBSCRIPTION) ??
-        (subscriptionType as any).astNode,
-    );
+    if (rootType != null && !isObjectType(rootType)) {
+      const operationTypeStr = capitalize(operationType);
+      const rootTypeStr = inspect(rootType);
+      context.reportError(
+        operationType === OperationTypeNode.QUERY
+          ? `${operationTypeStr} root type must be Object type, it cannot be ${rootTypeStr}.`
+          : `${operationTypeStr} root type must be Object type if provided, it cannot be ${rootTypeStr}.`,
+        getOperationTypeNode(schema, operationType) ??
+          (rootType as any).astNode,
+      );
+    }
   }
 }