expose theThemeContext to use the new context hook (segmentio#578)

src/index.js

@@ -59,7 +59,7 @@ export {
 export { SidebarTab, Tab, Tablist, TabNavigation } from './tabs'
 export { TagInput } from './tag-input'
 export { TextInput, TextInputField } from './text-input'
-export { ThemeProvider, ThemeConsumer, withTheme, defaultTheme } from './theme'
+export { ThemeContext, ThemeProvider, ThemeConsumer, withTheme, defaultTheme } from './theme'
 export { Textarea } from './textarea'
 export { toaster } from './toaster'
 export { Tooltip } from './tooltip'

src/theme/index.js

@@ -1,3 +1,3 @@
 export { default as defaultTheme } from './src/default-theme'
-export { ThemeProvider, ThemeConsumer } from './src/ThemeContext'
+export { default as ThemeContext, ThemeProvider, ThemeConsumer } from './src/ThemeContext'
 export { default as withTheme } from './src/withTheme'

src/theme/src/ThemeContext.js

@@ -4,9 +4,11 @@ import defaultTheme from './default-theme'
 /**
  * Use React 16.3+ createContext API.
  */
+const ThemeContext = React.createContext(defaultTheme)
 const {
   Provider: ThemeProvider,
   Consumer: ThemeConsumer
-} = React.createContext(defaultTheme)
+} = ThemeContext
 
+export default ThemeContext
 export { ThemeProvider, ThemeConsumer }