FormData.ts

import path from 'node:path';

import _FormData from 'form-data';

// eslint-disable-next-line
const NON_ASCII_RE = /[^\x00-\x7F]/i;

export class FormData extends _FormData {
  _getContentDisposition(value: any, options: any): string | undefined {
    // support non-ascii filename
    // https://github.com/form-data/form-data/pull/571
    let filename;
    let contentDisposition;

    if (typeof options.filepath === 'string') {
      // custom filepath for relative paths
      filename = path.normalize(options.filepath).replace(/\\/g, '/');
    } else if (options.filename || value.name || value.path) {
      // custom filename take precedence
      // formidable and the browser add a name property
      // fs- and request- streams have path property
      filename = path.basename(options.filename || value.name || value.path);
    } else if (value.readable && value.hasOwnProperty('httpVersion')) {
      // or try http response
      filename = path.basename(value.client._httpMessage.path || '');
    }

    if (filename) {
      // https://datatracker.ietf.org/doc/html/rfc6266#section-4.1
      // support non-ascii filename
      contentDisposition = 'filename="' + filename + '"';
      if (NON_ASCII_RE.test(filename)) {
        contentDisposition += "; filename*=UTF-8''" + encodeURIComponent(filename);
      }
    }

    return contentDisposition;
  }

  /**
   * Convert FormData to Buffer by consuming the CombinedStream.
   * This is needed for Bun compatibility since Bun's undici
   * doesn't support Node.js Stream objects as request body.
   *
   * Note: CombinedStream (which form-data extends) requires
   * resume() to start data flow, unlike standard Readable streams.
   */
  async toBuffer(): Promise<Buffer> {
    return new Promise<Buffer>((resolve, reject) => {
      const chunks: Buffer[] = [];
      this.on('data', (chunk: Buffer | string) => {
        // CombinedStream emits boundary/header strings alongside Buffer data
        chunks.push(typeof chunk === 'string' ? Buffer.from(chunk) : chunk);
      });
      this.on('end', () => resolve(Buffer.concat(chunks)));
      this.on('error', reject);
      // CombinedStream pauses by default and only starts
      // flowing when piped or explicitly resumed
      this.resume();
    });
  }
}