Google Recaptcha V2 implementation snippet with typescript, React & node

script.ts

// Client Side, React component

import { GOOGLE_RECAPTCHA_URL } from '../../../common/constants';
import { INVALID_CAPTCHA_PROVIDED } from '../../utils/constants';
import { MyWindow } from '../../../common/types/global';
import React from 'react';
import { RecaptchaResponse } from '../../../common/types/thirdParty';
import { SignupFormWithCaptcha } from '../../../common/types/signup';

const onRecaptchaScriptLoad = (): void => {
  window.grecaptcha.render('signup-recaptcha', {
    sitekey: siteKey,
  });
};

export const resetCaptcha = (): void => {
  window.grecaptcha.reset();
};

export const getCaptchaValue = (): string => {
  return window.grecaptcha.getResponse() || '';
};

export const loadScript = (): void => {
  const script = document.createElement('script');
  // onload method in the url should have the same name as the one being attached to window object
  script.src = `${GOOGLE_RECAPTCHA_URL}?onload=onRecaptchaScriptLoad&render=explicit`;
  script.async = true;
  script.defer = true;
  document.body.appendChild(script);
};

// Generated siteKey with google admin page
const siteKey = (window as MyWindow).conf.siteKey;

export const Recaptcha: React.FC<{}> = () => {
  React.useEffect(() => {
    (window as MyWindow).onRecaptchaScriptLoad = onRecaptchaScriptLoad;
    loadScript();
  }, []);

  return <div id="signup-recaptcha" />;
};

// Server Code

  export const validateRecaptchaResponse = async (
    payload: SignupFormWithCaptcha,
  ): Promise<RecaptchaResponse> => {
    const url = getEndpoint('google.recaptcha');
    const { captchaResponse } = payload;
    const params = {
        // recaptcha response/value sent from client
      response: captchaResponse,
      // get secret from .env file?
      secret: getPropertyFromEnvironment('RECAPTCHA_SITE_SECRET'),
    };

    const response = await axios<RecaptchaResponse>({
      method: 'post',
      url,
      params,
    });

    if (response.success) {
      return response;
    } else {
      throw new Error(INVALID_CAPTCHA_PROVIDED);
    }
}