Do not do any setup for beforeSave trigger if none is set for this className.

src/RestWrite.js

@@ -111,6 +111,11 @@ RestWrite.prototype.validateSchema = function() {
 // Runs any beforeSave triggers against this operation.
 // Any change leads to our data being mutated.
 RestWrite.prototype.runBeforeTrigger = function() {
+  // Avoid doing any setup for triggers if there is no 'beforeSave' trigger for this class.
+  if (!triggers.triggerExists(this.className, triggers.Types.beforeSave)) {
+    return Promise.resolve();
+  }
+
   // Cloud code gets a bit of extra data for its objects
   var extraData = {className: this.className};
   if (this.query && this.query.objectId) {

src/triggers.js

@@ -18,6 +18,10 @@ var getTrigger = function(className, triggerType) {
   return undefined;
 };
 
+function triggerExists(className: string, type: string): boolean {
+  return (getTrigger(className, type) != undefined);
+}
+
 var getRequestObject = function(triggerType, auth, parseObject, originalParseObject) {
   var request = {
     triggerName: triggerType,
@@ -96,5 +100,6 @@ module.exports = {
   getRequestObject: getRequestObject,
   inflate: inflate,
   maybeRunTrigger: maybeRunTrigger,
+  triggerExists: triggerExists,
   Types: Types
 };