#Core Services

This document introduces the three core services of maplebirchFramework: EventEmitter event bus, Logger logging service, and LanguageManager internationalization service.

#EventEmitter Event Bus

EventEmitter (accessible via maplebirch.tracer) provides a publish/subscribe event mechanism and is the foundation for inter-module communication within the framework. For full API reference, see EventEmitter.

#API

#Convenience Methods

MaplebirchCore proxies the event bus methods, which can be called directly on maplebirch:

maplebirch.on(
  ":passageend",
  () => {
    // Run on each passage end
  },
  "my handler",
);

maplebirch.once(":storyready", () => {
  // Run once after game starts
});

maplebirch.off(":passageend", "my handler");

#Built-in Events

#on vs once vs after

• on — Executes every time the event fires
• once — Executes once then auto-removes
• after — Executes after all on callbacks complete, then removes

#Custom Events

Besides built-in events, you can register arbitrary custom events:

// Register custom event listener
maplebirch.on(
  ":myCustomEvent",
  (data) => {
    console.log("Received data:", data);
  },
  "my custom handler",
);

// Trigger custom event
await maplebirch.trigger(":myCustomEvent", { key: "value" });

#Logger Logging Service

Logger (accessible via maplebirch.logger) provides a tiered logging system.

#Log Levels

Default level is INFO. Set to DEBUG to see all debug logs.

#Usage

// Via maplebirch convenience methods
maplebirch.log("Info message", "INFO");
maplebirch.log("Debug data", "DEBUG", someObject);
maplebirch.log("Warning message", "WARN");
maplebirch.log("Error message", "ERROR");

// Set log level
maplebirch.LogLevel = "DEBUG"; // Show all logs
maplebirch.LogLevel = "WARN"; // Show warnings and errors only

#Creating Module Logs

Use createlog() to create log functions with a prefix:

const log = maplebirch.tool.createlog("mymod");
log("Init complete"); // [maplebirch][INFO] [mymod] Init complete
log("Details", "DEBUG"); // [maplebirch][DEBUG] [mymod] Details

#IDB Configuration

Log level is read from the IndexedDB settings.DEBUG key. If DEBUG is true, log level is automatically set to DEBUG.

#LanguageManager Internationalization

LanguageManager (accessible via maplebirch.lang) provides multi-language translation support. For full API reference and configuration options, see LanguageManager.

#Supported Languages

• EN — English
• CN — Chinese

#Translation API

// Lookup by key
const text = maplebirch.t("greeting"); // Returns translation for current language

// Auto translation (reverse lookup)
const translated = maplebirch.auto("Hello"); // If current is CN, returns "你好"

#t() Method

maplebirch.t(key, space?)

• key — Translation key
• space — If true and current language is EN, append space to result

Lookup order: Memory cache → Current language → EN fallback → First available translation → [key]

#auto() Method

Reverse translation: Finds translation key by text content, then returns translation for current language.

Lookup order: Cache → Full search in memory translation table → IndexedDB async lookup

#Translation File Format

Supports JSON and YAML formats:

{
  "greeting": "你好",
  "farewell": "再见",
  "shop.welcome": "欢迎光临"
}

greeting: 你好
farewell: 再见
shop.welcome: 欢迎光临

#Switching Language

maplebirch.Language = "CN"; // Switch to Chinese
maplebirch.Language = "EN"; // Switch to English

Switching language will:

1. Update LanguageManager.language
2. Clear translation cache
3. Trigger :language event

#Data Persistence

Translation data is stored in IndexedDB:

• language-translations — Translation key-value pairs (indexed by mod and language)
• language-metadata — File hash (for incremental update detection)
• language-text_index — Text reverse index (for auto() lookup)

Translation files compute SHA-256 hash on import; import is skipped if file unchanged.