feat issue #1341 (Layouts) : taking into account code review's feedback

docs/layouts.md

@@ -134,8 +134,8 @@ Fields can be any of:
 - `%c` log category
 - `%h` hostname
 - `%m` log data
-- `%m{l}`, where l is an integer, log data.slice(l)
-- `%m{l,u}`, where l and u are integers, log data.slice(l,u)
+- `%m{l}` where l is an integer, log data.slice(l)
+- `%m{l,u}` where l and u are integers, log data.slice(l, u)
 - `%d` date, formatted - default is `ISO8601`, format options are: `ISO8601`, `ISO8601_WITH_TZ_OFFSET`, `ABSOLUTETIME`, `DATETIME`, or any string compatible with the [date-format](https://www.npmjs.com/package/date-format) library. e.g. `%d{DATETIME}`, `%d{yyyy/MM/dd-hh.mm.ss}`
 - `%%` % - for when you want a literal `%` in your output
 - `%n` newline

lib/layouts.js

@@ -101,8 +101,8 @@ function dummyLayout(loggingEvent) {
  *  - %c log category
  *  - %h hostname
  *  - %m log data
- *  - %m{l}, where l is an integer : log data.slice(l)
- *  - %m{l,u}, where l and u are integers : log data.slice(l,u)
+ *  - %m{l} where l is an integer, log data.slice(l)
+ *  - %m{l,u} where l and u are integers, log data.slice(l, u)
  *  - %d date in constious formats
  *  - %% %
  *  - %n newline
@@ -213,8 +213,11 @@ function patternLayout(pattern, tokens) {
   }
 
   function formatMessage(loggingEvent, specifier) {
-    const [lowerBound, upperBound] = specifier ? specifier.split(',') : [];
-    const dataSlice = loggingEvent.data.slice(lowerBound, upperBound);
+    let dataSlice = loggingEvent.data;
+    if (specifier) {
+      const [lowerBound, upperBound] = specifier.split(',');
+      dataSlice = dataSlice.slice(lowerBound, upperBound);
+    }
     return util.format(...dataSlice);
   }
 

test/tap/layouts-test.js

@@ -393,28 +393,7 @@ test('log4js layouts', (batch) => {
       assert.end();
     });
 
-    t.test(
-      '%m{P}, with P been an integer, shoud only consider data.slice( P )',
-      (assert) => {
-        const eventWithSeveralDataEntry = JSON.parse(JSON.stringify(event));
-        eventWithSeveralDataEntry.data = [
-          'This %s a %s like other ones',
-          "isn't",
-          'test',
-        ];
-        testPattern(
-          assert,
-          layout,
-          eventWithSeveralDataEntry,
-          tokens,
-          '%m{1}',
-          "isn't test"
-        );
-        assert.end();
-      }
-    );
-
-    t.test('%m{0, 1} should behave like a dummy layout', (assert) => {
+    t.test('%m{1} should only consider data.slice(1)', (assert) => {
       const eventWithSeveralDataEntry = JSON.parse(JSON.stringify(event));
       eventWithSeveralDataEntry.data = [
         'This %s a %s like other ones',
@@ -426,13 +405,31 @@ test('log4js layouts', (batch) => {
         layout,
         eventWithSeveralDataEntry,
         tokens,
-        '%m{0, 1}',
+        '%m{1}',
+        "isn't test"
+      );
+      assert.end();
+    });
+
+    t.test('%m{0,1} should behave like a dummy layout', (assert) => {
+      const eventWithSeveralDataEntry = JSON.parse(JSON.stringify(event));
+      eventWithSeveralDataEntry.data = [
+        'This %s a %s like other ones',
+        "isn't",
+        'test',
+      ];
+      testPattern(
+        assert,
+        layout,
+        eventWithSeveralDataEntry,
+        tokens,
+        '%m{0,1}',
         'This %s a %s like other ones'
       );
       assert.end();
     });
 
-    t.test('%m{1, 2} shoud only consider data.slice( 1, 2 )', (assert) => {
+    t.test('%m{1,2} should only consider data.slice(1, 2)', (assert) => {
       const eventWithSeveralDataEntry = JSON.parse(JSON.stringify(event));
       eventWithSeveralDataEntry.data = [
         'This %s a %s like other ones',
@@ -450,7 +447,7 @@ test('log4js layouts', (batch) => {
       assert.end();
     });
 
-    t.test('%m{1, 2} shoud only consider data.slice( 1, 2 )', (assert) => {
+    t.test('%m{1,2} should only consider data.slice(1, 2)', (assert) => {
       const eventWithSeveralDataEntry = JSON.parse(JSON.stringify(event));
       eventWithSeveralDataEntry.data = [
         'This %s a %s like other ones',
@@ -469,7 +466,7 @@ test('log4js layouts', (batch) => {
     });
 
     t.test(
-      '%m{0, -1} should consider the whole data except the last element',
+      '%m{0,-1} should consider the whole data except the last element',
       (assert) => {
         const eventWithSeveralDataEntry = JSON.parse(JSON.stringify(event));
         eventWithSeveralDataEntry.data = [