Http Request large JSON Response incompleted

ERROR Error: Uncaught (in promise): SyntaxError: Unterminated string in JSON at position 999958
SyntaxError: Unterminated string in JSON at position 999958 

  async graphQl(body) {
    const response = await fetch(url, {
      method: 'POST',
      headers: this.headers,
      body: JSON.stringify(body),
    });
    if (response.ok) {
      return await response.json();
    } else {
      throw new Error('GraphQL request failed: ' + response.status);
    }
  }

  try {
    const body = {
      query: req.payload,
    };
    console.log("body", body)
    let responseQL = await graphQl(body)
    res.send(JSON.stringify(responseQL));
  } catch (error) {
    res.json({ error: error });
  }