fix: fix loadComponents without valid state

Fix #34

Author: gregberge

src/loadComponents.js

@@ -3,7 +3,7 @@ import { LOADABLE, LOADABLE_STATE } from './constants'
 import * as componentTracker from './componentTracker'
 
 function loadState(rootState) {
-  if (!rootState.children) return null
+  if (!rootState.children) return Promise.resolve(null)
 
   return Promise.all(
     rootState.children.map(state => {
@@ -50,7 +50,7 @@ function loadComponents() {
   }
 
   const state = window[LOADABLE_STATE]
-  if (!state) {
+  if (!state || !state.children) {
     throw new Error(
       'loadable-components state not found. ' +
         'You have a problem server-side. ' +

src/loadComponents.test.js

@@ -30,4 +30,26 @@ describe('loadComponents', () => {
     expect(Component2.load).toHaveBeenCalled()
     expect(Component3.load).toHaveBeenCalled()
   })
+
+  it('should handle no LOADABLE_STATE', async () => {
+    delete window[LOADABLE_STATE]
+    expect.assertions(1)
+
+    try {
+      await loadComponents()
+    } catch (err) {
+      expect(err.message).toMatch(/loadable-components state not found/)
+    }
+  })
+
+  it('should handle no children', async () => {
+    delete window[LOADABLE_STATE].children
+    expect.assertions(1)
+
+    try {
+      await loadComponents()
+    } catch (err) {
+      expect(err.message).toMatch(/loadable-components state not found/)
+    }
+  })
 })