Function once

once<E>(eventName, listener, context?): void
Add a one-time listener for a given event.
Type Parameters
- E extends keyof Events
Parameters
- eventName: E
  The event name.
- listener: Events[E]
  The listener function.
- Optionalcontext: any
  The context to invoke the listener with.
Returns void
Example
```
me.event.once("event-name", myFunction, this);
```
- Defined in packages/melonjs/src/system/event.ts:419