Deciding when to trigger a trigger

HI is there any way to run a trigger eg beforeSave (_User) in certain cases, not every time I update User. I would like to decide when the trigger should be fired, is there any way?

Triggers will always fire, but you can program the function only on certain events.

Parse.Cloud.beforeSave(Parse.User, ({object, master, context}) => {
  if (!object.existed()) {
  // this will only fire on signups
  if (object.dirty("key")) {
   // this will only fire if key is updated
  if (context.key) {
   // this will only fire if context.key is passed 

And to pass context:, { context: { key: true } })