docs(subscriptions): updated subscriptions docs

docs/source/index.md

@@ -11,6 +11,6 @@ The process of setting up a GraphQL subscriptions server consist of the followin
 
 1. Declaring subscriptions in the GraphQL schema
 2. Setup a PubSub instance that our server will publish new events to
-3. Hook together `PubSub` evnet and GraphQL subscription.
+3. Hook together `PubSub` event and GraphQL subscription.
 4. Setting up `SubscriptionsServer`, a transport between the server and the clients
 

docs/source/lifecycle-events.md

@@ -7,7 +7,7 @@ order: 404
 
 * `onConnect` - called upon client connection, with the `connectionParams` passed to `SubscriptionsClient` - you can return a Promise and reject the connection by throwing an exception. The resolved return value will be appended to the GraphQL `context` of your subscriptions.
 * `onDisconnect` - called when the client disconnects.
-* `onOperation` - called when the client executes a GraphQL operation - use this method to create custom params that will be used when resolving the operarion.
+* `onOperation` - called when the client executes a GraphQL operation - use this method to create custom params that will be used when resolving the operation.
 * `onOperationDone` - called when client's operation has been done it's execution (for subscriptions called when unsubscribe, and for query/mutation called immediatly).
 
 ```js

docs/source/subscriptions-to-schema.md

@@ -46,4 +46,26 @@ Then, later on your code, you can publish data to your topic by using `pubsub.pu
 
 ```js
 pubsub.publish('commentAdded', { commentAdded: { id: 1, content: 'Hello!' }})
-```
+```
+
+<h2 id="subscription-server">Payload Transformation</h2>
+
+When using `subscribe` field, it's also possible to manipulate the event payload before running it throught the GraphQL execution engine.
+
+Add `resolve` method near your `subscribe` and change the payload as you wish:
+
+
+```js
+const rootResolver = {
+    Subscription: {
+        commentAdded: {
+          resolve: (payload) => {
+            return {
+              customData: payload,
+            };
+          },
+          subscribe: () => pubsub.asyncIterator('commentAdded')
+        }
+    },
+};
+```