Add options to stream email content

[Ohadleshno15]

Add Configurable Text Streaming Mode

Summary

Adds streamText option to enable zero-buffering streaming of email text content instead of accumulating in memory.

Changes

• New Option: streamText: true - streams each text part individually
• Default Behavior: streamText: false - maintains backward compatibility
• Zero Buffering: Text content streams directly without memory accumulation
• Individual Parts: Each MIME text part (plain/html) emits separately

Usage

// Streaming mode - no memory buffering
const parser = new MailParser({ streamText: true });
parser.on('data', (data) => {
  if (data.type === 'text') {
    data.content.pipe(process.stdout); // Stream directly
  }
});

// Traditional mode (default) - backward compatible
const parser = new MailParser();
parser.on('data', (data) => {
  if (data.type === 'text') {
    console.log(data.text, data.textAsHtml); // Aggregated content
  }
});

Tests

• ✅ Streaming mode validation
• ✅ Individual part content verification
• ✅ Backward compatibility assurance

Benefits: Handles large emails efficiently without memory accumulation while maintaining full backward compatibility.

[CLAassistant]

All committers have signed the CLA.