1 files changed, 63 insertions, 0 deletions
diff --git a/std/log/logger.ts b/std/log/logger.ts
new file mode 100644
index 000000000..482743b23
--- /dev/null
+++ b/std/log/logger.ts
@@ -0,0 +1,63 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { LogLevel, getLevelByName, getLevelName } from "./levels.ts";
+import { BaseHandler } from "./handlers.ts";
+
+export interface LogRecord {
+  msg: string;
+  args: unknown[];
+  datetime: Date;
+  level: number;
+  levelName: string;
+}
+
+export class Logger {
+  level: number;
+  levelName: string;
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  handlers: any[];
+
+  constructor(levelName: string, handlers?: BaseHandler[]) {
+    this.level = getLevelByName(levelName);
+    this.levelName = levelName;
+
+    this.handlers = handlers || [];
+  }
+
+  _log(level: number, msg: string, ...args: unknown[]): void {
+    if (this.level > level) return;
+
+    // TODO: it'd be a good idea to make it immutable, so
+    // no handler mangles it by mistake
+    // TODO: iterpolate msg with values
+    const record: LogRecord = {
+      msg: msg,
+      args: args,
+      datetime: new Date(),
+      level: level,
+      levelName: getLevelName(level)
+    };
+    this.handlers.forEach((handler): void => {
+      handler.handle(record);
+    });
+  }
+
+  debug(msg: string, ...args: unknown[]): void {
+    this._log(LogLevel.DEBUG, msg, ...args);
+  }
+
+  info(msg: string, ...args: unknown[]): void {
+    this._log(LogLevel.INFO, msg, ...args);
+  }
+
+  warning(msg: string, ...args: unknown[]): void {
+    this._log(LogLevel.WARNING, msg, ...args);
+  }
+
+  error(msg: string, ...args: unknown[]): void {
+    this._log(LogLevel.ERROR, msg, ...args);
+  }
+
+  critical(msg: string, ...args: unknown[]): void {
+    this._log(LogLevel.CRITICAL, msg, ...args);
+  }
+}