logger
The logger option provides custom logging for React Compiler events during compilation.
{
  logger: {
    logEvent(filename, event) {
      console.log(`[Compiler] ${event.kind}: ${filename}`);
    }
  }
}Reference
logger 
Configures custom logging to track compiler behavior and debug issues.
Type
{
  logEvent: (filename: string | null, event: LoggerEvent) => void;
} | nullDefault value
null
Methods
- logEvent: Called for each compiler event with the filename and event details
Event types
- CompileSuccess: Function successfully compiled
- CompileError: Function skipped due to errors
- CompileDiagnostic: Non-fatal diagnostic information
- CompileSkip: Function skipped for other reasons
- PipelineError: Unexpected compilation error
- Timing: Performance timing information
Caveats
- Event structure may change between versions
- Large codebases generate many log entries
Usage
Basic logging
Track compilation success and failures:
{
  logger: {
    logEvent(filename, event) {
      switch (event.kind) {
        case 'CompileSuccess': {
          console.log(`✅ Compiled: ${filename}`);
          break;
        }
        case 'CompileError': {
          console.log(`❌ Skipped: ${filename}`);
          break;
        }
        default: {}
      }
    }
  }
}Detailed error logging
Get specific information about compilation failures:
{
  logger: {
    logEvent(filename, event) {
      if (event.kind === 'CompileError') {
        console.error(`\nCompilation failed: ${filename}`);
        console.error(`Reason: ${event.detail.reason}`);
        if (event.detail.description) {
          console.error(`Details: ${event.detail.description}`);
        }
        if (event.detail.loc) {
          const { line, column } = event.detail.loc.start;
          console.error(`Location: Line ${line}, Column ${column}`);
        }
        if (event.detail.suggestions) {
          console.error('Suggestions:', event.detail.suggestions);
        }
      }
    }
  }
}