Added some basic Flow types to get things started

.flowconfig

@@ -12,6 +12,8 @@
 
 [options]
 module.system=haste
+module.system.node.resolve_dirname=node_modules
+module.system.node.resolve_dirname=src
 
 esproposal.class_static_fields=enable
 esproposal.class_instance_fields=enable

flow-typed/gatsby-link.js

@@ -0,0 +1,3 @@
+declare module 'gatsby-link' {
+  declare module.exports: any;
+}

flow-typed/glamor.js

@@ -0,0 +1,7 @@
+declare module 'glamor' {
+  declare module.exports: {
+    css: {
+      global: (...params: any) => void,
+    },
+  };
+}

flow-typed/graphql.js

@@ -0,0 +1 @@
+declare function graphql(...params: any): any;

src/components/Container/Container.js

@@ -5,6 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *
  * @emails react-core
+ * @flow
  */
 
 'use strict';
@@ -13,11 +14,13 @@ import React from 'react';
 
 import {media} from 'theme';
 
+import type {Node} from 'react';
+
 /**
  * This component wraps page content sections (eg header, footer, main).
  * It provides consistent margin and max width behavior.
  */
-const Container = ({children}) => (
+const Container = ({children}: {children: Node}) => (
   <div
     css={{
       paddingLeft: 20,

src/html.js

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *
  * @emails react-core
-*/
+ */
 
 'use strict';
 

src/index.js

@@ -1 +0,0 @@
-var foo = 'bar';

src/pages/404.js

@@ -5,7 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  *
  * @emails react-core
-*/
+ * @flow
+ */
 
 'use strict';
 

src/pages/blog/all.html.js

@@ -5,7 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  *
  * @emails react-core
-*/
+ * @flow
+ */
 
 'use strict';
 
@@ -19,7 +20,13 @@ import {colors, media, sharedStyles} from 'theme';
 import toCommaSeparatedList from 'utils/toCommaSeparatedList';
 import MetaTitle from 'templates/components/MetaTitle';
 
-const AllBlogPosts = ({data}) => (
+import type {allMarkdownRemarkData} from 'types';
+
+type Props = {
+  data: allMarkdownRemarkData,
+};
+
+const AllBlogPosts = ({data}: Props) => (
   <Container>
     <div css={sharedStyles.articleLayout.container}>
       <div css={sharedStyles.articleLayout.content}>

src/pages/jsx-compiler.html.js

@@ -5,7 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  *
  * @emails react-core
-*/
+ * @flow
+ */
 
 'use strict';
 

src/prism-styles.js

@@ -5,7 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  *
  * @emails react-core
-*/
+ * @flow
+ */
 
 'use strict';
 

src/site-constants.js

@@ -4,19 +4,15 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @emails react-core
+ * @providesModule site-constants
  * @flow
-*/
+ */
 
 'use strict';
 
-/**
+// NOTE: We can't just use `location.toString()` because when we are rendering
- * Variables shared by multiple components.
+// the SSR part in node.js we won't have a proper location.
- */
+const urlRoot = 'https://reactjs.org';
+const version = '16.0.0';
 
-export default {
+export {urlRoot, version};
-  // NOTE: We can't just use `location.toString()` because when we are rendering
-  // the SSR part in node.js we won't have a proper location.
-  urlRoot: 'https://reactjs.org',
-  version: '16.0.0',
-};

src/theme.js

@@ -4,9 +4,9 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @emails react-core
+ * @providesModule theme
  * @flow
-*/
+ */
 
 'use strict';
 
@@ -399,9 +399,4 @@ const sharedStyles = {
   },
 };
 
-export default {
+export {colors, fonts, media, sharedStyles};
-  colors,
-  fonts,
-  media,
-  sharedStyles,
-};

src/types.js

@@ -0,0 +1,44 @@
+/**
+ * Copyright (c) 2013-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @emails react-core
+ * @flow
+ */
+
+export type Author = {
+  name: string,
+  url: string,
+};
+
+export type Node = {
+  excerpt: string,
+  fields: {
+    date?: string,
+    path: string,
+    redirect: string,
+    slug: string,
+  },
+  frontmatter: {
+    author?: Array<Author>,
+    next?: string,
+    prev?: string,
+    title: string,
+  },
+  html: string,
+  id: string,
+};
+
+export type Edge = {
+  node: Node,
+};
+
+export type allMarkdownRemarkData = {
+  allMarkdownRemark: {
+    edges: Array<Edge>,
+  },
+};
+
+export type markdownRemarkData = Node;

src/utils/createLink.js

@@ -109,7 +109,7 @@ const linkCss = {
   },
 };
 
-export default {
+export {
   createLinkBlog,
   createLinkCommunity,
   createLinkDocs,