loopCommand(command, duration) {
        const id = ++this._lastId;
        this.aCommands.looped.push({id, command, duration, time: duration + this.nTime});
        return id;
    }
/**
     * executes a command again and again.
     * time duration between each execution is specified
     * @param command {function} function to be called back
     * @param duration {number} number of milliseconds between one execution and the next
     */
executes a command again and again.
time duration between each execution is specified
@param command {function} function to be called back
@param duration {number} number of milliseconds between one execution and the next
executes a command again and again . time duration between each execution is specified @param command { function } function to be called back @param duration { number } number of milliseconds between one execution and the next
loopCommand(command, duration) {
        const id = ++this._lastId;
        this.aCommands.looped.push({id, command, duration, time: duration + this.nTime});
        return id;
    }
loopCommand ( command , duration ) { const id = ++ this . _lastId ; this . aCommands . looped . push ( { id , command , duration , time : duration + this . nTime } ) ; return id ; }
executes a command again and again.
executes a command again and again .