better error message for related errors

Author: EmrysMyrddin

.changeset/rude-squids-accept.md

@@ -0,0 +1,5 @@
+---
+'graphql-yoga': patch
+---
+
+Improve error messages in case of `operatinName` related errors.

packages/graphql-yoga/src/plugins/request-validation/use-check-graphql-query-params.ts

@@ -1,4 +1,5 @@
-import { createGraphQLError } from '@graphql-tools/utils';
+import { Kind } from 'graphql';
+import { createGraphQLError, isDocumentNode } from '@graphql-tools/utils';
 import type { GraphQLParams } from '../../types.js';
 import type { Plugin } from '../types.js';
 
@@ -138,6 +139,55 @@ export function useCheckGraphQLQueryParams(extraParamNames?: string[]): Plugin {
     onParams({ params }) {
       checkGraphQLQueryParams(params, extraParamNames);
     },
+    onParse() {
+      return ({
+        result,
+        context: {
+          request,
+          params: { operationName },
+        },
+      }) => {
+        // Run only if this is a Yoga request
+        // the `request` might be missing when using graphql-ws for example
+        // in which case throwing an error would abruptly close the socket
+        if (!request || !isDocumentNode(result)) {
+          return;
+        }
+
+        let message: string | undefined;
+
+        const operations = result.definitions.filter(
+          definition => definition.kind === Kind.OPERATION_DEFINITION,
+        );
+
+        if (operationName) {
+          const operationExists = operations.some(
+            operation => operation.name?.value === operationName,
+          );
+
+          if (!operationExists) {
+            if (operations.length === 1) {
+              message = `Operation name "${operationName}" doesn't match the name defined in the query.`;
+            } else {
+              message = `Could not determine what operation to execute. There is no operation "${operationName}" in the query.`;
+            }
+          }
+        } else if (operations.length > 1) {
+          message =
+            'Could not determine what operation to execute. The query contains multiple operations, an operation name must be provided';
+        }
+
+        if (message) {
+          throw createGraphQLError(message, {
+            extensions: {
+              http: {
+                status: 400,
+              },
+            },
+          });
+        }
+      };
+    },
   };
 }
 

packages/graphql-yoga/src/plugins/request-validation/use-prevent-mutation-via-get.ts

@@ -1,29 +1,15 @@
-import { DocumentNode, getOperationAST, GraphQLError, OperationDefinitionNode } from 'graphql';
+import { DocumentNode, GraphQLError, Kind } from 'graphql';
 import { Maybe } from '@envelop/core';
-import { createGraphQLError } from '@graphql-tools/utils';
+import { createGraphQLError, isDocumentNode } from '@graphql-tools/utils';
 import type { YogaInitialContext } from '../../types.js';
 import type { Plugin } from '../types.js';
 
-export function assertMutationViaGet(
-  method: string,
-  document: Maybe<DocumentNode>,
-  operationName?: string,
-) {
-  const operation: OperationDefinitionNode | undefined = document
-    ? getOperationAST(document, operationName) ?? undefined
-    : undefined;
+export function assertMutationViaGet(method: string, document: Maybe<DocumentNode>) {
+  const isMutation =
+    document?.definitions.find(def => def.kind === Kind.OPERATION_DEFINITION)?.operation ===
+    'mutation';
 
-  if (!operation) {
-    throw createGraphQLError('Could not determine what operation to execute.', {
-      extensions: {
-        http: {
-          status: 400,
-        },
-      },
-    });
-  }
-
-  if (operation.operation === 'mutation' && method === 'GET') {
+  if (isMutation && method === 'GET') {
     throw createGraphQLError('Can only perform a mutation operation from a POST request.', {
       extensions: {
         http: {
@@ -41,15 +27,7 @@ export function usePreventMutationViaGET(): Plugin<YogaInitialContext> {
   return {
     onParse() {
       // We should improve this by getting Yoga stuff from the hook params directly instead of the context
-      return ({
-        result,
-        context: {
-          request,
-          // the `params` might be missing in cases where the user provided
-          // malformed context to getEnveloped (like `yoga.getEnveloped({})`)
-          params: { operationName } = {},
-        },
-      }) => {
+      return ({ result, context: { request } }) => {
         // Run only if this is a Yoga request
         // the `request` might be missing when using graphql-ws for example
         // in which case throwing an error would abruptly close the socket
@@ -67,7 +45,9 @@ export function usePreventMutationViaGET(): Plugin<YogaInitialContext> {
           throw result;
         }
 
-        assertMutationViaGet(request.method, result, operationName);
+        if (isDocumentNode(result)) {
+          assertMutationViaGet(request.method, result);
+        }
       };
     },
   };