reCaptcha Enterprise assessment Node.js code breaks on unexpected '.'

Question

I'm trying to set up reCaptcha Enterprise in a React/Node.js application. I have successfully set up the reCaptcha to work on the frontend and it is generating a token and passing it to the backend for assessment. The problem I can't seem to get around is the Node.js assessment example code from Google breaks, giving a the message SyntaxError: Unexpected token '.'. Specifically, this seems to happen when creating a new RecaptchaEnterpriseServiceClient. I suspect there might be an issue with authentication using Application Default Credentials, but I haven't seen any evidence of errors in the backend logging.

First, in the Google Cloud Console I give my IAM user roles for reCAPTCHA Enterprise Admin and reCAPTCHA Enterprise Agent.

I'm running the backend in Docker. I use the gcloud cli to authenticate my IAM user on my host machine, generate the ADC and mount it on the backend container using docker compose.

...
volumes:
      - $HOME/.config/gcloud/application_default_credentials.json:/gcp/creds.json:ro
...

The json credentials look something like this.

{
  "account": "",
  "client_id": "764....apps.googleusercontent.com",
  "client_secret": "d-F.....",
  "quota_project_id": "my-project-name",
  "refresh_token": "1//04k.....",
  "type": "authorized_user",
  "universe_domain": "googleapis.com"
}

I set the environment variable Google uses to find the ADC.

GOOGLE_APPLICATION_CREDENTIALS="/gcp/creds.json"

I add the example assessment method to my backend code.

const { RecaptchaEnterpriseServiceClient } = require('@google-cloud/recaptcha-enterprise');

const createAssessment = async (assessObj) => {

  const { projectID, recaptchaKey, token, recaptchaAction } = assessObj;
  // console.log("projectID", projectID, "recaptchaKey", recaptchaKey, "token", token, "recaptchaAction", recaptchaAction)

  // Create the reCAPTCHA client.
  // TODO: Cache the client generation code (recommended) or call client.close() before exiting the method.
  const client = new RecaptchaEnterpriseServiceClient();
  const projectPath = client.projectPath(projectID);

  // Build the assessment request.
  const request = ({
    assessment: {
      event: {
        token: token,
        siteKey: recaptchaKey,
      },
    },
    parent: projectPath,
  });

  const [ response ] = await client.createAssessment(request);

  // Check if the token is valid.
  if (!response.tokenProperties.valid) {
    console.log(`The CreateAssessment call failed because the token was: ${response.tokenProperties.invalidReason}`);
    return null;
  }

  // Check if the expected action was executed.
  // The `action` property is set by user client in the grecaptcha.enterprise.execute() method.
  if (response.tokenProperties.action === recaptchaAction) {
    // Get the risk score and the reason(s).
    // For more information on interpreting the assessment, see:
    // https://cloud.google.com/recaptcha-enterprise/docs/interpret-assessment
    console.log(`The reCAPTCHA score is: ${response.riskAnalysis.score}`);
    response.riskAnalysis.reasons.forEach((reason) => {
      console.log(reason);
    });

    return response.riskAnalysis.score;
  } else {
    console.log("The action attribute in your reCAPTCHA tag does not match the action you are expecting to score");
    return null;
  }
}

module.exports = { createAssessment }

I call createAssessment from my registration controller.

    try {
        const test = await createAssessment({
            projectID:"my-project-name", 
            recaptchaKey:process.env.GOOGLE_CAPTCHA_SITE_KEY, 
            token: recaptchaToken,
            recaptchaAction: 'register'
        })
        console.log(test)
    } catch(err){
        console.log(`Failed to get assessment: ${err}`)
    }

I would expect to see some assessment console logs, but, looking at the logging for the backend container I see ...

Failed to get assessment: SyntaxError: Unexpected token '.'