[relay] Make sure optional props remain optional.

types/react-relay/index.d.ts

@@ -21,8 +21,10 @@ import * as RelayRuntimeTypes from "relay-runtime";
 // ~~~~~~~~~~~~~~~~~~~~~
 // Utility types
 // ~~~~~~~~~~~~~~~~~~~~~
+
+// Taken from https://github.com/pelotom/type-zoo
 type Diff<T extends string, U extends string> = ({ [P in T]: P } & { [P in U]: never } & { [x: string]: never })[T];
-type Omit<T, K extends keyof T> = { [P in Diff<keyof T, K>]: T[P] };
+type Omit<T, K extends keyof T> = Pick<T, Diff<keyof T, K>>;
 
 type RemoveRelayProp<P> = Omit<P & { relay: never }, "relay">;
 

types/react-relay/test/react-relay-tests.tsx

@@ -75,6 +75,7 @@ const Story = (() => {
         relay: RelayRefetchProp;
         story: Story_story;
         onLike: StoryLike;
+        ignoreMe?: {};
     }
 
     interface State {
@@ -161,6 +162,7 @@ const Feed = (() => {
         relay: RelayProp;
         feed: FeedStories_feed;
         onStoryLike: StoryLike;
+        ignoreMe?: {};
     }
 
     const FeedStories: React.SFC<Props> = ({ feed, onStoryLike, relay }) => {
@@ -223,6 +225,7 @@ type UserFeed_user = {
         relay: RelayPaginationProp;
         loadMoreTitle: string;
         user: UserFeed_user;
+        ignoreMe?: {};
     }
 
     class UserFeed extends React.Component<Props> {