Working with User Data in BJS: Properties and Storage

// Store different types of data
User.setProperty("username", "john_doe");              // String
User.setProperty("age", 25);                            // Number
User.setProperty("is_premium", true);                   // Boolean
User.setProperty("preferences", {theme: "dark", lang: "en"}); // Object

// Retrieve stored data
var username = User.getProperty("username");
var age = User.getProperty("age");
var isPremium = User.getProperty("is_premium");
var preferences = User.getProperty("preferences");

if (preferences) {
    Bot.sendMessage("Your theme: " + preferences.theme);
}

if (User.getProperty("first_visit") === undefined) {
    // First time user
    User.setProperty("first_visit", Date.now());
    Bot.sendMessage("Welcome! Thanks for your first visit.");
} else {
    var visits = User.getProperty("visit_count") || 0;
    User.setProperty("visit_count", visits + 1);
    Bot.sendMessage("Welcome back! This is your " + (visits + 1) + " visit.");
}