- Service Worker: Save on IndexDb and Sync to send after to the DB.

- Insert record on MongoDb, POST, GET.

src/js/utility.js

@@ -0,0 +1,91 @@
+console.log('utility.js')
+
+var dbPromise = idb.open('mydb', 10, function (db) {
+  console.log('OPEN MYDB')
+  if (!db.objectStoreNames.contains('sync_todos')) {
+    db.createObjectStore('sync_todos', { keyPath: 'id' });
+  }
+  if (!db.objectStoreNames.contains('todos')) {
+    db.createObjectStore('todos', { keyPath: 'id' });
+  }
+});
+
+function writeData(st, data) {
+  console.log('writeData', st, data);
+  return dbPromise
+    .then(function (db) {
+      var tx = db.transaction(st, 'readwrite');
+      var store = tx.objectStore(st);
+      store.put(data);
+      return tx.complete;
+    });
+}
+
+function readAllData(st) {
+  console.log('readAllData', st);
+  return dbPromise
+    .then(function (db) {
+      var tx = db.transaction(st, 'readonly');
+      var store = tx.objectStore(st);
+      return store.getAll();
+    });
+}
+
+function clearAllData(st) {
+  console.log('clearAllData', st);
+  return dbPromise
+    .then(function (db) {
+      var tx = db.transaction(st, 'readwrite');
+      var store = tx.objectStore(st);
+      store.clear();
+      return tx.complete;
+    });
+}
+
+function deleteItemFromData(st, id) {
+  console.log('deleteItemFromData', st, 'ID:', id);
+  dbPromise
+    .then(function (db) {
+
+      var tx = db.transaction(st, 'readwrite');
+      var store = tx.objectStore(st);
+
+      try {
+        store.delete(id);
+        return tx.complete;
+      } catch (e) {
+        return false;
+      }
+    })
+    .then(function (res) {
+      if (res)
+        console.log('Item deleted!');
+    });
+}
+
+function urlBase64ToUint8Array(base64String) {
+  var padding = '='.repeat((4 - base64String.length % 4) % 4);
+  var base64 = (base64String + padding)
+    .replace(/\-/g, '+')
+    .replace(/_/g, '/');
+
+  var rawData = window.atob(base64);
+  var outputArray = new Uint8Array(rawData.length);
+
+  for (var i = 0; i < rawData.length; ++i) {
+    outputArray[i] = rawData.charCodeAt(i);
+  }
+  return outputArray;
+}
+
+function dataURItoBlob(dataURI) {
+  var byteString = atob(dataURI.split(',')[1]);
+  var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0]
+  var ab = new ArrayBuffer(byteString.length);
+  var ia = new Uint8Array(ab);
+  for (var i = 0; i < byteString.length; i++) {
+    ia[i] = byteString.charCodeAt(i);
+  }
+  var blob = new Blob([ab], { type: mimeString });
+  return blob;
+}