Export Logger class (#2181)

* export Logger class

* Add semicolon and a couple of tests

* Update index.d.ts

* Update README.md

* refactor: 🔥 dead code

* revert: not so dead code

Author: Faithfinder

README.md

@@ -226,6 +226,7 @@ const logger = winston.createLogger({
 
 const childLogger = logger.child({ requestId: '451' });
 ```
+> `.child` is likely to be bugged if you're also extending the `Logger` class, due to some implementation details that make `this` keyword to point to unexpected things. Use with caution.
 
 ### Streams, `objectMode`, and `info` objects
 

index.d.ts

@@ -121,10 +121,10 @@ declare namespace winston {
     defaultMeta?: any;
 
     log: LogMethod;
-    add(transport: Transport): Logger;
-    remove(transport: Transport): Logger;
-    clear(): Logger;
-    close(): Logger;
+    add(transport: Transport): this;
+    remove(transport: Transport): this;
+    clear(): this;
+    close(): this;
 
     // for cli and npm levels
     error: LeveledLogMethod;
@@ -153,11 +153,11 @@ declare namespace winston {
     stream(options?: any): NodeJS.ReadableStream;
 
     startTimer(): Profiler;
-    profile(id: string | number, meta?: Record<string, any>): Logger;
+    profile(id: string | number, meta?: Record<string, any>): this;
 
     configure(options: LoggerOptions): void;
 
-    child(options: Object): Logger;
+    child(options: Object): this;
 
     isLevelEnabled(level: string): boolean;
     isErrorEnabled(): boolean;

lib/winston.js

@@ -40,6 +40,11 @@ exports.format = logform.format;
  * @type {function}
  */
 exports.createLogger = require('./winston/create-logger');
+/**
+ * Expose core Logging-related prototypes.
+ * @type {function}
+ */
+exports.Logger = require('./winston/logger');
 /**
  * Expose core Logging-related prototypes.
  * @type {Object}
@@ -172,5 +177,4 @@ warn.forFunctions(exports, 'deprecated', [
   'extend'
 ]);
 warn.forProperties(exports, 'deprecated', ['emitErrs', 'levelLength']);
-// Throw a useful error when users attempt to run `new winston.Logger`.
-warn.moved(exports, 'createLogger', 'Logger');
+

lib/winston/common.js

@@ -34,21 +34,6 @@ exports.warn = {
       obj[prop] = exports.warn[type](prop);
     });
   },
-  moved(obj, movedTo, prop) {
-    function movedNotice() {
-      return () => {
-        throw new Error([
-          format('winston.%s was moved in winston@3.0.0.', prop),
-          format('Use a winston.%s instead.', movedTo)
-        ].join('\n'));
-      };
-    }
-
-    Object.defineProperty(obj, prop, {
-      get: movedNotice,
-      set: movedNotice
-    });
-  },
   forProperties(obj, type, props) {
     props.forEach(prop => {
       const notice = exports.warn[type](prop);

test/integration/logger.test.js

@@ -0,0 +1,17 @@
+const assume = require('assume');
+const winston = require('../../lib/winston');
+
+const Logger = winston.Logger;
+
+describe('Logger class', () => {
+  it('that Logger class is exported', () => {
+    Logger === require('../../lib/winston/logger');
+  });
+
+  it('can be inherited', () => {
+    class CustomLogger extends Logger {}
+    const instance = new CustomLogger();
+    assume(instance).instanceOf(CustomLogger);
+    assume(instance).instanceOf(Logger);
+  });
+});