nl_tokens: Install an event handler for the given event name
pl_tokens: function ( eventName , handler ) { if ( typeof ( eventName ) !== 'string' ) { throw new Error ( 'Argument eventName should be a string' ) ; } if ( typeof ( handler ) !== 'function' ) { throw <mask> Error ( 'Argument handler should be a function' ) ; } log ( '[Eventhandling] Adding event listener' , eventName ) ; this . _validateEvent ( eventName ) ; this . _handlers [ eventName ] . push ( handler ) ; }