init

plugins/preventMultitabs.js

@@ -0,0 +1,36 @@
+/* eslint-disable no-console */
+export default ({ store, isHMR, app }, inject) => {
+  inject('preventMultitabs', main)
+}
+function main(store) {
+  const id = Date.now()
+  window.id = id
+  window.localStorage.setItem('firstTab', id)
+
+  const onLocalStorageEvent = function(e) {
+    // the second tab will write its id to this key. The first one will notice it
+    if (e.key === 'firstTab') {
+      const newID = Date.now()
+      console.log('Another tab detected. Setting the new page id', newID)
+      setTimeout(() => {
+        window.localStorage.secondTab = newID // this is going to be a message for the second tab
+      }, 200)
+    }
+
+    // the second tab proccesses the message
+    if (e.key === 'secondTab' && window.id.toString() === window.localStorage.firstTab) {
+      console.log('There is another tab that already opened. We will close this one')
+      window.multipleTabsDetected = true
+      window.onbeforeunload = null
+      window.alert(
+        'Multiple tabs opened. Your page will be closed. Please only use single instance of https://tornado.cash'
+      )
+      window.location = 'https://twitter.com/tornadocash'
+    }
+  }
+
+  // this event will only trigger when a window other than itself makes changes to local storage.
+  setTimeout(() => {
+    window.addEventListener('storage', onLocalStorageEvent, false)
+  }, 100)
+}