on() 
Attaches a listener function to an event, allowing it to be called when the event is emitted. This method is almost an alias of addListener(), but does not support the once parameter.
Example 
typescript
instance.on("foo", () => {
  /* [...] */
});Parameters 
| Parameter | Type | Default | Description | 
|---|---|---|---|
| event | string | symbol | The event name. Expects an ESMitterEventName. | |
| fn | unknown | The function that will be called when the event is emitted. | |
| context | unknown | undefined | The context to invoke the listener with. | 
Returns 
| Type | Description | 
|---|---|
| ESMitter | The ESMitter instance, allowing for method chaining. | 
once() 
To attach a one-time listener, use once() instead.