From 7737143c918cd76cc0d2318afc206011d9c7f628 Mon Sep 17 00:00:00 2001
From: Anton Johansson <antoon.johansson@gmail.com>
Date: Sat, 9 Mar 2019 00:46:08 +0100
Subject: [PATCH] Add support for `loggerName`

---
 README.md     | 14 ++++++++++++++
 index.test.js | 13 +++++++++++++
 lib/logger.js | 14 +++++++++++---
 3 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index bf482af..e66cfd9 100644
--- a/README.md
+++ b/README.md
@@ -88,6 +88,20 @@ Level and output:
 | `{ level: 'fatal' }` | -     | -     | -    | -    | -     | O     |
 | `{ level: 'none' }`  | -     | -     | -    | -    | -     | -     |
 
+## loggerName
+Specify the name of the logger. Useful when logging from different files.
+```js
+const Logger = require('node-json-logger');
+const logger = new Logger({ loggerName: 'server/index.js' });
+
+logger.info('message');
+```
+
+Output:
+```json
+{"timestamp":"2001-03-14T01:00:00.000Z","level":"info","loggerName":"server/index.js","message":"message"}
+```
+
 ## timestamp
 Specify enable or disable timestamp. (optional, default is true)
 
diff --git a/index.test.js b/index.test.js
index e2782b4..9d26acc 100644
--- a/index.test.js
+++ b/index.test.js
@@ -162,3 +162,16 @@ test('Timezone can be declared with config.', t => {
         t.is('America/Sao_Paulo', logger.options.timezone);
     });
 });
+
+test('Logger name can be set', t => {
+    const console = new Console();
+    const logger = new Logger({ level: 'info', loggerName: 'server/index.js' });
+    const timestamp = "2001-03-14T01:00:00.000Z";
+    logger.timestamp = () => timestamp;
+    logger.writeln = o => console.log(JSON.stringify(o));
+
+    logger.info('Hello world!');
+    const expected = `{"timestamp":"${timestamp}","level":"info","loggerName":"server/index.js","message":"Hello world!"}`;
+    const actual = console.last();
+    t.is(expected, actual);
+});
diff --git a/lib/logger.js b/lib/logger.js
index 31b6f6d..13a0a2a 100644
--- a/lib/logger.js
+++ b/lib/logger.js
@@ -17,9 +17,17 @@ module.exports = class Logger {
 
         this.writeln = $object => console.log(JSON.stringify($object));
 
-        this.head = this.options.timestamp
-            ? level => ({ timestamp: this.timestamp(), level: level })
-            : level => ({ level: level });
+        this.head = level => {
+            const data = {};
+            if (this.options.timestamp) {
+                data.timestamp = this.timestamp();
+            }
+            data.level = level;
+            if (this.options.loggerName) {
+                data.loggerName = this.options.loggerName;
+            }
+            return data;
+        };
 
         this.trace = this.debug = this.info = this.warn = this.error = this.fatal = () => { };
         const level = levels.includes(this.options.level) ? this.options.level : 'debug';