Return Google Gemini Response as JSON in NestJS app

I'm following a tutor on how to implement Google Gemini's API. He used Next.js API routes but I'm using NestJS as a seperate backend. We're using the same prompts, specifying to Gemini that the data must be returned in JSON format.

His response comes correct in a JSON format like this:

But mine comes as a text/string:

This is my code:

async generateVideo(prompt: string) {
    try {
      const model = this.genAI.getGenerativeModel({
        model: 'gemini-1.5-flash',
      });

      const generationConfig = {
        temperature: 1,
        topP: 0.95,
        topK: 64,
        maxOutputTokens: 8192,
        responseMimeType: 'application/json',
      };

      const chatSession = model.startChat({
        generationConfig,
        history: [ /*Removed because it was too long */ ],
      });

      const result = await chatSession.sendMessage(prompt.toString());
      console.log(result.response.text());

      return {
        data: result.response.text(), // I guess I made an error here?
      };
    } catch (error) {}

This modification uses JSON.parse to convert the text response into a JSON object before returning it. Now, data will hold the parsed JSON instead of a raw string.

const result = await chatSession.sendMessage(prompt.toString()); console.log(result.response.text());

  const parsedData = JSON.parse(result.response.text()); // Parse the JSON response

  return {
    data: parsedData,
  };