es5->es6

Author: yurijmikhalevich

lib/winston-mongodb.js

@@ -174,17 +174,17 @@ winston.transports.MongoDB = MongoDB;
  * Used by winston Logger.close on transports.
  */
 MongoDB.prototype.close = function() {
-  var self = this;
-  if (this.logDb) {
-    this.logDb.close(function(err) {
-      if (err) {
-        console.error('Winston MongoDB transport encountered on error during' +
-            ' closing.', err);
-      } else {
-        self.logDb = null;
-      }
-    });
+  if (!this.logDb) {
+    return;
   }
+  this.logDb.close(err=>{
+    if (err) {
+      console.error('Winston MongoDB transport encountered on error during' +
+          ' closing.', err);
+    } else {
+      this.logDb = null;
+    }
+  });
 };
 
 
@@ -193,60 +193,51 @@ MongoDB.prototype.close = function() {
  * @param {string} level Level at which to log the message.
  * @param {string} msg Message to log
  * @param {Object=} opt_meta Additional metadata to attach
- * @param {Function} callback Continuation to respond to when complete.
+ * @param {Function} cb Continuation to respond to when complete.
  */
-MongoDB.prototype.log = function(level, msg, opt_meta, callback) {
+MongoDB.prototype.log = function(level, msg, opt_meta, cb) {
   if (!this.logDb) {
-    this._opQueue.push({
-      method: 'log',
-      args: arguments
-    });
+    this._opQueue.push({method: 'log', args: arguments});
     return;
   }
-
-  var self = this;
-
   /**
    * Avoid reentrancy that can be not assumed by database code.
    * If database logs, better not to call database itself in the same call.
    */
-  process.nextTick(function() {
-    if (self.silent) {
-      callback(null, true);
+  process.nextTick(()=>{
+    if (this.silent) {
+      cb(null, true);
       return;
     }
-
     function onError(err) {
-      self.emit('error', err);
-      callback(err, null);
+      this.emit('error', err);
+      cb(err, null);
     }
-
-    self.logDb.collection(self.collection, function(err, col) {
+    this.logDb.collection(this.collection, (err, col)=>{
       if (err) {
         onError(err);
         return;
       }
 
-      var entry = {};
-      entry.message = self.decolorize ? msg.replace(/\u001b\[[0-9]{1,2}m/g, '') : msg;
+      let entry = {};
+      entry.message = this.decolorize ? msg.replace(/\u001b\[[0-9]{1,2}m/g, '') : msg;
       entry.timestamp = new Date();
       entry.level = level;
       entry.meta = helpers.prepareMetaData(opt_meta);
-      if (self.storeHost) {
-        entry.hostname = self.hostname;
+      if (this.storeHost) {
+        entry.hostname = this.hostname;
       }
-      if (self.label) {
-        entry.label = self.label;
+      if (this.label) {
+        entry.label = this.label;
       }
 
-      col.insertOne(entry, function(err) {
+      col.insertOne(entry, err=>{
         if (err) {
           onError(err);
           return;
         }
-
-        self.emit('logged');
-        callback(null, true);
+        this.emit('logged');
+        cb(null, true);
       });
     });
   });