Initial 1.0.0 commit (library extracted from existing project).

src/logger.ts

@@ -0,0 +1,108 @@
+import { LogMessage, LogLevel } from './log-message';
+import LogAppender from './log-appender';
+
+export type DeferredMsg = () => string | object;
+export type MessageType = string | DeferredMsg | object;
+
+export class Logger {
+  public appenders: LogAppender[] = [];
+
+  public constructor(
+    public readonly name: string,
+    private parentLogger?: Logger,
+    public threshold?: LogLevel
+  ) {}
+
+  public createChildLogger(name: string, threshold?: LogLevel): Logger {
+    return new Logger(name, this, threshold);
+  }
+
+  public doLog(
+    level: LogLevel,
+    message: Error | MessageType,
+    stacktrace?: string
+  ): void {
+    if (level < this.getEffectiveThreshold()) {
+      return;
+    }
+
+    const logMsg: LogMessage = {
+      scope: this.name,
+      level,
+      message: '',
+      stacktrace: '',
+      timestamp: new Date()
+    };
+
+    if (message === undefined || message === null) {
+      logMsg.message = message;
+      logMsg.stacktrace = stacktrace == null ? '' : stacktrace;
+    } else if ((message as DeferredMsg).call !== undefined) {
+      logMsg.message = (message as DeferredMsg)();
+      logMsg.stacktrace = stacktrace == null ? '' : stacktrace;
+    } else if (message instanceof Error) {
+      const error = message as Error;
+      logMsg.error = error;
+      logMsg.message = `${error.name}: ${error.message}`;
+      logMsg.stacktrace = error.stack == null ? '' : error.stack;
+    } else {
+      // string | object
+      logMsg.message = message;
+      logMsg.stacktrace = stacktrace == null ? '' : stacktrace;
+    }
+
+    this.sendToAppenders(logMsg);
+  }
+
+  public trace(message: Error | MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.TRACE, message, stacktrace);
+  }
+
+  public debug(message: Error | MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.DEBUG, message, stacktrace);
+  }
+
+  public log(message: MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.LOG, message, stacktrace);
+  }
+
+  public info(message: MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.INFO, message, stacktrace);
+  }
+
+  public warn(message: MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.WARN, message, stacktrace);
+  }
+
+  public error(message: Error | MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.ERROR, message, stacktrace);
+  }
+
+  public fatal(message: Error | MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.FATAL, message, stacktrace);
+  }
+
+  protected sendToAppenders(logMsg: LogMessage) {
+    this.appenders.forEach(app => {
+      app.appendMessage(logMsg);
+    });
+
+    if (this.parentLogger) {
+      this.parentLogger.sendToAppenders(logMsg);
+    }
+  }
+
+  protected getEffectiveThreshold(): LogLevel {
+    if (this.threshold) {
+      return this.threshold;
+    }
+    if (this.parentLogger) {
+      return this.parentLogger.getEffectiveThreshold();
+    }
+
+    // should never happen (root logger should always have a threshold
+    return LogLevel.ALL;
+  }
+}
+
+export default Logger;