Merge e22cd4e into 20776fc

lib/winston/logger.js

@@ -44,30 +44,10 @@ class Logger extends Transform {
 
   child(defaultRequestMetadata) {
     const logger = this;
-    return Object.create(logger, {
-      write: {
-        value: function (info) {
-          const infoClone = Object.assign(
-            {},
-            defaultRequestMetadata,
-            info
-          );
-
-          // Object.assign doesn't copy inherited Error
-          // properties so we have to do that explicitly
-          //
-          // Remark (indexzero): we should remove this
-          // since the errors format will handle this case.
-          //
-          if (info instanceof Error) {
-            infoClone.stack = info.stack;
-            infoClone.message = info.message;
-          }
-
-          logger.write(infoClone);
-        }
-      }
-    });
+    const childLogger = Object.create(logger);
+    childLogger.parentLogger = logger;
+    childLogger.defaultMeta = defaultRequestMetadata;
+    return childLogger;
   }
 
   /**
@@ -117,6 +97,7 @@ class Logger extends Transform {
     this.rejections = new RejectionHandler(this);
     this.profilers = {};
     this.exitOnError = exitOnError;
+    this.parentLogger = null;
 
     // Add all transports we have been provided.
     if (transports) {
@@ -233,34 +214,28 @@ class Logger extends Transform {
     }
 
     const [meta] = splat;
+    const info = {};
+    this._addDefaultMeta(info);
+    let mergeMessage = false;
     if (typeof meta === 'object' && meta !== null) {
       // Extract tokens, if none available default to empty array to
       // ensure consistancy in expected results
       const tokens = msg && msg.match && msg.match(formatRegExp);
 
       if (!tokens) {
-        const info = Object.assign({}, this.defaultMeta, meta, {
-          [LEVEL]: level,
-          [SPLAT]: splat,
-          level,
-          message: msg
-        });
-
-        if (meta.message) info.message = `${info.message} ${meta.message}`;
-        if (meta.stack) info.stack = meta.stack;
-
-        this.write(info);
-        return this;
+        assignWithGetters(info, meta);
+        mergeMessage = true;
       }
     }
-
-    this.write(Object.assign({}, this.defaultMeta, {
+    assignWithGetters(info, {
       [LEVEL]: level,
       [SPLAT]: splat,
       level,
       message: msg
-    }));
-
+    });
+    if (mergeMessage && meta.message) info.message = `${info.message} ${meta.message}`;
+    if (mergeMessage && meta.stack) info.stack = meta.stack;
+    this.write(info);
     return this;
   }
 
@@ -624,6 +599,13 @@ class Logger extends Transform {
     );
   }
 
+  write(chunk, ...args) {
+    if (!(chunk instanceof Error)) {
+      chunk = Object.assign({}, chunk);
+    }
+    super.write(chunk, ...args);
+  }
+
   /**
    * Bubbles the `event` that occured on the specified `transport` up
    * from this instance.
@@ -647,9 +629,12 @@ class Logger extends Transform {
   }
 
   _addDefaultMeta(msg) {
-    if (this.defaultMeta) {
-      Object.assign(msg, this.defaultMeta);
+    const merged = {};
+    if (this.parentLogger) {
+      this.parentLogger._addDefaultMeta(merged);
     }
+    assignWithGetters(merged, this.defaultMeta, msg);
+    assignWithGetters(msg, merged);
   }
 }
 
@@ -674,4 +659,20 @@ Object.defineProperty(Logger.prototype, 'transports', {
   }
 });
 
+function assignWithGetters(target, ...sources) {
+  // eslint-disable-next-line no-shadow
+  return sources.reduce((target, source) => {
+    // eslint-disable-next-line eqeqeq
+    if (source != null) {
+      const enumerableKeys = Object.keys(source);
+      const symbolKeys = Object.getOwnPropertySymbols(source);
+      // Don't use Reflect.ownKeys here because we only want to assign enumerable ones
+      for (const key of enumerableKeys.concat(symbolKeys)) {
+        Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key));
+      }
+    }
+    return target;
+  }, target);
+}
+
 module.exports = Logger;

test/logger.test.js

@@ -68,38 +68,33 @@ describe('Logger', function () {
   });
 
   it('new Logger({ levels }) custom methods are not bound to instance', function (done) {
-    var logger = winston.createLogger({
-      level: 'error',
-      exitOnError: false,
-      transports: []
-    });
 
-    let logs = [];
-    let extendedLogger = Object.create(logger, {
-      write: {
-        value: function(...args) {
-          logs.push(args);
-          if (logs.length === 4) {
-            assume(logs.length).is.eql(4);
-            assume(logs[0]).is.eql([{ test: 1, level: 'info' }]);
-            assume(logs[1]).is.eql([{ test: 2, level: 'warn' }]);
-            assume(logs[2]).is.eql([{ message: 'test3', level: 'info' }])
-            assume(logs[3]).is.eql([{ with: 'meta',
-              test: 4,
-              level: 'warn',
-              message: 'a warning'
-            }]);
-
-            done();
-          }
-        }
+    var expected = [
+      { test: 1, level: 'info' },
+      { test: 2, level: 'warn' },
+      { message: 'test3', level: 'info' },
+      { with: 'meta',
+        test: 4,
+        level: 'warn',
+        message: 'a warning'
+      }
+    ];
+
+    var i = 0;
+    var logger = helpers.createLogger(function (chunk, encoding, next) {
+      assume(i).is.lessThan(expected.length);
+      assume(chunk).is.eql(expected[i]);
+      i++;
+      next();
+      if (i === expected.length) {
+        done();
       }
     });
 
-    extendedLogger.log('info', { test: 1 });
-    extendedLogger.log('warn', { test: 2 });
-    extendedLogger.info('test3');
-    extendedLogger.warn('a warning', { with: 'meta', test: 4 });
+    logger.log('info', { test: 1 });
+    logger.log('warn', { test: 2 });
+    logger.info('test3');
+    logger.warn('a warning', { with: 'meta', test: 4 });
   });
 
   it('.add({ invalid Transport })', function () {