fix(logger): flush log buffer on critical() when flushOnErrorLog is e…

packages/logger/src/Logger.ts

@@ -408,9 +408,6 @@ class Logger extends Utility implements LoggerInterface {
    * @param extraInput - The extra input to log.
    */
   public error(input: LogItemMessage, ...extraInput: LogItemExtraInput): void {
-    if (this.#bufferConfig.enabled && this.#bufferConfig.flushOnErrorLog) {
-      this.flushBuffer();
-    }
     this.processLogItem(LogLevelThreshold.ERROR, input, extraInput);
   }
 
@@ -1063,6 +1060,15 @@ class Logger extends Utility implements LoggerInterface {
     input: LogItemMessage,
     extraInput: LogItemExtraInput
   ): void {
+    if (
+      this.#bufferConfig.enabled &&
+      this.#bufferConfig.flushOnErrorLog &&
+      logLevel >= LogLevelThreshold.ERROR &&
+      logLevel < LogLevelThreshold.SILENT
+    ) {
+      this.flushBuffer();
+    }
+
     const traceId = getXRayTraceIdFromEnv();
     if (traceId !== undefined && this.shouldBufferLog(traceId, logLevel)) {
       try {

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

@@ -259,6 +259,38 @@ describe('Buffer logs', () => {
     expect(console.error).toBeCalledTimes(1);
   });
 
+  it('it flushes the buffer when a critical log is logged', () => {
+    // Prepare
+    const logger = new Logger({
+      logLevel: LogLevel.ERROR,
+      logBufferOptions: { enabled: true },
+    });
+
+    // Act
+    logger.debug('This is a log message');
+    logger.critical('This is a critical message');
+
+    // Assess
+    expect(console.debug).toHaveBeenCalledTimes(1);
+    expect(console.error).toHaveBeenCalledTimes(1); // critical uses console.error
+  });
+
+  it('does not flush on critical logs when flushOnErrorLog is disabled', () => {
+    // Prepare
+    const logger = new Logger({
+      logLevel: LogLevel.ERROR,
+      logBufferOptions: { enabled: true, flushOnErrorLog: false },
+    });
+
+    // Act
+    logger.debug('This is a log message');
+    logger.critical('This is a critical message');
+
+    // Assess
+    expect(console.debug).toHaveBeenCalledTimes(0);
+    expect(console.error).toHaveBeenCalledTimes(1); // critical uses console.error
+  });
+
   it('passes down the same buffer config to child loggers', () => {
     // Prepare
     const logger = new Logger({