In case if you want the bot accept user command and admin command, you can try this example, or using switch-case:
var admin = "76561..."; //this is admin Steam ID
client.on('friendMessage', function (steamID, message) {
if((steamID == admin) && (message== "!command1")){
client.chatMessage(steamID, 'admin command 1');
}
else if((steamID == admin) && (message== "!command2")){
client.chatMessage(steamID, 'admin command 2');
}
else if(message== "!user1"){
client.chatMessage(steamID, 'user command 1');
}
else if(message== "!help"){
client.chatMessage(steamID, '!help command');
}
else {
client.chatMessage(steamID, 'command not found, use !help');
}
});