inital work

packages/core/utils/array.js

@@ -20,13 +20,30 @@ export function deleteItems(array, ...items) {
 }
 
 export function findById(array, id) {
+  if (!array) return false;
   return array.find((item) => item.id === id);
 }
 
 export function hasItem(array, item) {
+  if (!array) return false;
   return array.indexOf(item) > -1;
 }
 
+export async function diff(arr1, arr2, action) {
+  let length = arr1.length + arr2.length;
+  for (var i = 0; i < length; ++i) {
+    var actionKey = "delete";
+    var item = arr1[i];
+
+    if (i >= arr1.length) {
+      var actionKey = "insert";
+      var item = arr2[i - arr1.length];
+    }
+
+    await action(item, actionKey);
+  }
+}
+
 function deleteAtIndex(array, index) {
   if (index === -1) return false;
   array.splice(index, 1);