Either set vuex store or register text module in store mixin

When a component from the NPM package is used by a vue app with an own
vuex store, we have to expand this store with our text module.

Signed-off-by: Jonas <[email protected]>

Author: mejo-

src/mixins/store.js

@@ -20,7 +20,7 @@
  *
  */
 
-import store from '../store/index.js'
+import store, { textModule } from '../store/index.js'
 
 /**
  * This mixin is required since we cannot be sure that the root Vue instance has
@@ -35,7 +35,11 @@ export default {
 	},
 	beforeMount() {
 		if (typeof this.$store === 'undefined') {
+			// Store is undefined, e.g. when used through `viewer.js`
 			this.$store = store
+		} else if (!this.$store.hasModule('text')) {
+			// Store lacks text modul (another store exists), e.g. when used as component via NPM package
+			this.$store.registerModule('text', textModule)
 		}
 	},
 }

src/store/index.js

@@ -36,7 +36,7 @@ const persistentStorage = getBuilder('text').persist().build()
 
 Vue.use(Vuex)
 
-const textModule = {
+export const textModule = {
 	state: {
 		showAuthorAnnotations: persistentStorage.getItem('showAuthorAnnotations') === 'true',
 		currentSession: persistentStorage.getItem('currentSession'),