function exec()

in packages/flow-dev-tools/src/utils/async.js [32:59]

• 27 lines of code
• 6 McCabe index (conditional complexity)

function exec(cmd: string, options?: ExecOpts): Promise<string> {
  return new Promise((resolve, reject) => {
    const cp = cp_exec(cmd, options, (err, stdout, stderr) => {
      if (err == null) {
        resolve(stdout.toString());
      } else {
        reject([err, stdout, stderr]);
      }
    });
    if (options != null && options.stdin != null) {
      // If we just write a giant string it can lead to a crash
      const chunks = splitIntoChunks(options.stdin, STDIN_WRITE_CHUNK_SIZE);
      const write = (chunkIndex: number) => {
        if (chunkIndex >= chunks.length) {
          cp.stdin.end();
          return;
        }
        const canContinue = cp.stdin.write(chunks[chunkIndex], 'utf8');
        if (canContinue) {
          write(chunkIndex + 1);
        } else {
          cp.stdin.once('drain', () => write(chunkIndex + 1));
        }
      };
      write(0);
    }
  });
}