docs(remote-schema): adjust Fetcher interface

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ### vNEXT
 
-* ...
+* Properly document the `FetcherOperation` to accept a `DocumentNode` [PR #933](https://github.com/apollographql/graphql-tools/pull/933) [Issue #891](https://github.com/apollographql/graphql-tools/issues/891)
 
 ### v3.1.1
 

docs/source/remote-schemas.md

@@ -104,7 +104,7 @@ You can also use a fetcher (like apollo-fetch or node-fetch) instead of a link.
 type Fetcher = (operation: Operation) => Promise<ExecutionResult>;
 
 type Operation {
-  query: string;
+  query: DocumentNode;
   operationName?: string;
   variables?: Object;
   context?: Object;
@@ -162,7 +162,8 @@ Basic usage
 ```js
 import fetch from 'node-fetch';
 
-const fetcher = async ({ query, variables, operationName, context }) => {
+const fetcher = async ({ query: queryDocument, variables, operationName, context }) => {
+  const query = print(queryDocument);
   const fetchResult = await fetch('http://api.githunt.com/graphql', {
     method: 'POST',
     headers: {
@@ -187,7 +188,8 @@ Authentication headers from context
 ```js
 import fetch from 'node-fetch';
 
-const fetcher = async ({ query, variables, operationName, context }) => {
+const fetcher = async ({ query: queryDocument, variables, operationName, context }) => {
+  const query = print(queryDocument);
   const fetchResult = await fetch('http://api.githunt.com/graphql', {
     method: 'POST',
     headers: {