lib: optimize logger by checking hasSubscribers early

Author: mertcanaltin

benchmark/logger/vs-pino.js

@@ -143,4 +143,4 @@ function main({ n, logger, scenario }) {
 
     destination.flushSync();
   }
-}
+}

lib/logger.js

@@ -24,6 +24,7 @@ const {
 
 const Utf8Stream = require('internal/streams/fast-utf8-stream');
 const diagnosticsChannel = require('diagnostics_channel');
+const { kEmptyObject } = require('internal/util');
 
 // Create channels for each log level
 const channels = {
@@ -282,6 +283,20 @@ class Logger {
       return;
     }
 
+    if (typeof msgOrObj === 'string') {
+      if (fields !== undefined) {
+        validateObject(fields, 'fields');
+      }
+    } else if (!this._isError(msgOrObj)) {
+      validateObject(msgOrObj, 'obj');
+      validateString(msgOrObj.msg, 'obj.msg');
+    }
+
+    const channel = channels[level];
+    if (!channel.hasSubscribers) {
+      return;
+    }
+
     let msg;
     let logFields;
 
@@ -294,10 +309,7 @@ class Logger {
     } else if (typeof msgOrObj === 'string') {
       msg = msgOrObj;
       logFields = fields || kEmptyObject;
-      validateObject(logFields, 'fields');
     } else {
-      validateObject(msgOrObj, 'obj');
-      validateString(msgOrObj.msg, 'obj.msg');
       const { msg: extractedMsg, ...restFields } = msgOrObj;
       msg = extractedMsg;
       logFields = restFields;
@@ -315,10 +327,7 @@ class Logger {
       fields: logFields,
     };
 
-    const channel = channels[level];
-    if (channel.hasSubscribers) {
-      channel.publish(record);
-    }
+    channel.publish(record);
   }
 
   /**