[breaking] Change the method signature to a filter function to be c…

…onsistent with `rewriter` and log functions.

README.md

@@ -671,14 +671,14 @@ Both filters and rewriters are simple Arrays of functions which can be provided
 ``` js
 var logger = new winston.Logger({
   rewriters: [function (level, msg, meta) { /* etc etc */ }]
-  filters:   [function (msg, meta, level) { /* etc etc */ }]
+  filters:   [function (level, msg, meta) { /* etc etc */ }]
 })
 ```
 
 Like any Array they can also be modified at runtime with no adverse side-effects to the `winston` internals.
 
 ``` js
-logger.filters.push(function(msg, meta, level) {
+logger.filters.push(function(level, msg, meta) {
   return meta.production
     ? maskCardNumbers(msg)
     : msg;

lib/winston/logger.js

@@ -141,7 +141,7 @@ Logger.prototype.log = function (level) {
   });
 
   this.filters.forEach(function(filter) {
-    var filtered = filter(msg, meta, level, self);
+    var filtered = filter(level, msg, meta, self);
     if (typeof filtered === 'string')
       msg = filtered;
     else {

test/log-filter-test.js

@@ -49,7 +49,7 @@ vows.describe('winston/logger/filter').addBatch({
     ]}),
     "the filters.push() method, adding a filter only for the message": {
       topic: function (logger) {
-        logger.filters.push(function (msg) {
+        logger.filters.push(function (level, msg) {
           return maskCardNumbers(msg);
         });
 
@@ -76,7 +76,7 @@ vows.describe('winston/logger/filter').addBatch({
     }),
     "the filters.push() method adding a filter for the message and metadata": {
       topic: function (logger) {
-        logger.filters.push(function (msg, meta) {
+        logger.filters.push(function (level, msg, meta) {
           return maskSecrets(msg, meta);
         });