feat: allow empty array in createAll method

lib/dao.js

@@ -512,10 +512,25 @@ DataAccessObject.createAll = function(dataArray, options, cb) {
   options = options || {};
   cb = cb || utils.createPromiseCallback();
 
-  assert(typeof dataArray === 'object' && dataArray.length,
-    'The data argument must be an array with length > 0');
+  assert(typeof dataArray === 'object' && Array.isArray(dataArray),
+  'The data argument must be an array');
   assert(typeof options === 'object', 'The options argument must be an object');
   assert(typeof cb === 'function', 'The cb argument must be a function');
+  // If the dataArray is empty, we return an empty array or an error
+  if (dataArray.length === 0) {
+    if (options.allowEmptyArray === true) {
+     process.nextTick(function() {
+        cb(null, []);
+      });
+    } else {
+      process.nextTick(function() {
+        const err = new Error('The data argument must be an array with length > 0');
+        err.statusCode = 400;
+        cb(err);
+      });
+    }
+    return cb.promise;
+  }
 
   const validationPromises = [];
   for (let index = 0; index < dataArray.length; index++) {