index.js
/**
     * @public
     * @function listenerCount
     * @description Returns the number of listeners listening to the event named eventName.
     * @memberof SafeEmitter#
     * @param {!string} eventName event name
     * @returns {number}
     */
@public
@function listenerCount
@description Returns the number of listeners listening to the event named eventName.
@memberof SafeEmitter
@param {!string} eventName event name
@returns {number}
@public @function listenerCount @description Returns the number of listeners listening to the event named eventName . @memberof SafeEmitter @param { !string } eventName event name @returns { number }
listenerCount(eventName) {
        const evt = events.get(this);
        return evt.has(eventName) ? evt.get(eventName).length : 0;
    }
listenerCount ( eventName ) { const evt = events . get ( this ) ; return evt . has ( eventName ) ? evt . get ( eventName ) . length : 0 ; }
@public
 @function listenerCount
 @description Returns the number of listeners listening to the event named eventName.
@public @function listenerCount @description Returns the number of listeners listening to the event named eventName .