Retained tab state using location hash (#161)

assets/js/app.js

@@ -22,6 +22,7 @@ import { Socket } from 'phoenix'
 import { LiveSocket } from 'phoenix_live_view'
 import topbar from '../vendor/topbar'
 import Alpine from 'alpinejs'
+import './tabs'
 
 window.Alpine = Alpine
 Alpine.start()

assets/js/tabs.js

@@ -0,0 +1,20 @@
+window.setTabIndex = (index) => {
+  window.location.hash = `tab-${index}`
+
+  return index
+}
+
+// The conditionals and currIndex stuff ensures that
+// the tab index is always set to 0 if the hash is empty
+// AND other hash values are ignored
+window.getTabIndex = (currIndex) => {
+  if (window.location.hash === '' || window.location.hash === '#') {
+    return 0
+  }
+
+  if (window.location.hash.startsWith('#tab-')) {
+    return parseInt(window.location.hash.replace('#tab-', ''))
+  }
+
+  return currIndex
+}