fix: set correct loading state if component is already loaded. (#64)

src/loadable.js

@@ -49,7 +49,7 @@ function loadable(
       this.state = {
         Component: LoadableComponent.Component,
         error: null,
-        loading: true,
+        loading: !LoadableComponent.Component,
       }
       this.mounted = false
       this.loadingPromise = null

src/loadable.test.js

@@ -41,6 +41,7 @@ describe('#loadable', () => {
     await Loadable.load()
     const wrapper = mount(<Loadable />)
     expect(wrapper.contains(<Dummy />)).toBe(true)
+    expect(wrapper.state().loading).toBe(false)
   })
 
   it('should do nothing if component is not mounted', async () => {