fix(logger): Format the stack trace as an array of strings in dev mode

When POWERTOOLS_DEV is enabled, the stack trace will be split on newline characters to create an array. This improves readability compared to a single long string

Author: ConnorKirk

packages/logger/src/formatter/LogFormatter.ts

@@ -131,6 +131,13 @@ abstract class LogFormatter {
       }
     }
 
+    if (
+      this.envVarsService?.isDevMode() &&
+      typeof formattedError.stack === 'string'
+    ) {
+      formattedError.stack = formattedError.stack.split('\n');
+    }
+
     return formattedError;
   }
 

packages/logger/tests/unit/initializeLogger.test.ts

@@ -163,4 +163,27 @@ describe('Log levels', () => {
 
     vi.useRealTimers();
   });
+
+  it('splits the stack trace into an array when POWERTOOLS_DEV is set', () => {
+    // Prepare
+    const logger = new Logger();
+    const err = new Error('Hello, world!');
+
+    // Act
+    logger.error('Error occured', err);
+
+    // Assess
+    expect(console.error).toHaveBeenCalledTimes(1);
+    expect(console.error).toHaveLoggedNth(
+      1,
+      expect.objectContaining({
+        error: {
+          location: expect.any(String),
+          message: 'Hello, world!',
+          name: 'Error',
+          stack: expect.any(Array),
+        },
+      })
+    );
+  });
 });

packages/logger/tests/unit/workingWithkeys.test.ts

@@ -56,7 +56,7 @@ describe('Working with keys', () => {
           location: expect.any(String),
           message: 'Something happened!',
           name: 'Error',
-          stack: expect.any(String),
+          stack: expect.any(Array),
         },
       },
       info: 'adds the message and error',
@@ -72,7 +72,7 @@ describe('Working with keys', () => {
           location: expect.any(String),
           message: 'Something happened!',
           name: 'Error',
-          stack: expect.any(String),
+          stack: expect.any(Array),
         },
       },
       info: 'adds the message and custom error',
@@ -104,7 +104,7 @@ describe('Working with keys', () => {
               location: expect.any(String),
               message: 'Arbitrary object error',
               name: 'Error',
-              stack: expect.any(String),
+              stack: expect.any(Array),
             },
           },
         },