WanLinLin/index.html

## index.html
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>React Recaptcha Example</title>
</head>
<body>
  <script>
    function onRecaptchaLoaded() {
      // code to inform recaptcha react component that recaptcha is loaded
      // by setting isRecaptchaLoaded prop
    }
  </script>
  <script src="https://www.google.com/recaptcha/api.js?onload=onRecaptchaLoaded" async defer></script>
</body>
</html>

## recaptcha.jsx
import React from 'react'
import PropTypes from 'prop-types'

import {GOOGLE_RECAPTCHA_SITE_KEY} from 'constant'

/**
 * recaptcha v2 I'm not a robot
 * See https://developers.google.com/recaptcha/docs/display
 */
class Recaptcha extends React.Component {
  constructor() {
    super()
    this.ref = null
    this.state = {
      // is recaptcha element rendered, it can only be rendered once
      rendered: false,
      currentWidth: 0,
      parentWidth: 0,
    }

    this.handleOnExpired = this.handleOnExpired.bind(this)
    this.handleOnError = this.handleOnError.bind(this)
    this.bindRef = this.bindRef.bind(this)
    this.renderRecaptcha = this.renderRecaptcha.bind(this)
    this.resetRecaptcha = this.resetRecaptcha.bind(this)
  }

  handleOnExpired() {
    this.props.onResponseChange()
  }

  handleOnError() {
    // Executed when recaptcha encounters an error (usually network
    // connectivity) and cannot continue until connectivity is restored.
    //
    // If the error callback is not provided, recaptcha will pop an alert which
    // is duplicated with our offline modal. So provide the callback and leave
    // it blank.
  }

  bindRef(ref) {
    this.ref = ref
  }

  renderRecaptcha() {
    if (!this.props.isRecaptchaLoaded || this.state.rendered) {
      return
    }

    this.widgetId = grecaptcha.render(this.ref, {
      sitekey: GOOGLE_RECAPTCHA_SITE_KEY,

      size: 'normal',

      // executed when the recaptcha response expires (2 mins) and the user
      // needs to re-verify
      'expired-callback': this.handleOnExpired,

      'error-callback': this.handleOnError,

      // executed when the user passes the challenge. The g-recaptcha-response
      // token is passed to the callback
      callback: this.props.onResponseChange,
    })

    this.setState({rendered: true})
    this.setState({parentWidth: this.ref.parentNode.clientWidth})
    this.setState({currentWidth: this.ref.clientWidth})
  }

  resetRecaptcha() {
    grecaptcha.reset(this.widgetId)
  }

  componentDidMount() {
    this.renderRecaptcha()
  }

  componentDidUpdate(prevProps) {
    if (!prevProps.shouldResetRecaptcha && this.props.shouldResetRecaptcha) {
      this.resetRecaptcha()
    }
    this.renderRecaptcha()
  }

  render() {
    const style = {display: 'inline-block'}
    const {currentWidth, parentWidth} = this.state
    return (

      // Scale recaptcha size to fit its parant width for small screen size mobile.
      <div
        ref={this.bindRef}
        style={
          currentWidth !== 0 ? {
            ...style,
            transform: `scale(${ currentWidth > parentWidth ? parentWidth / currentWidth : 1 })`,
            transformOrigin: 0,
          } : style
        }
      ></div>
    )
  }
}

Recaptcha.propTypes = {
  // The response is given when user passes the challenge. Should send the
  // response along with form data to API to verify the user is not a robot.
  // See https://developers.google.com/recaptcha/docs/verify
  onResponseChange: PropTypes.func.isRequired,

  isRecaptchaLoaded: PropTypes.bool.isRequired,
  shouldResetRecaptcha: PropTypes.bool.isRequired,
}

export default Recaptcha
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<title>React Recaptcha Example</title>
	</head>
	<body>
	<script>
	function onRecaptchaLoaded() {
	// code to inform recaptcha react component that recaptcha is loaded
	// by setting isRecaptchaLoaded prop
	}
	</script>
	<script src="https://www.google.com/recaptcha/api.js?onload=onRecaptchaLoaded" async defer></script>
	</body>
	</html>
	import React from 'react'
	import PropTypes from 'prop-types'

	import {GOOGLE_RECAPTCHA_SITE_KEY} from 'constant'

	/**
	* recaptcha v2 I'm not a robot
	* See https://developers.google.com/recaptcha/docs/display
	*/
	class Recaptcha extends React.Component {
	constructor() {
	super()
	this.ref = null
	this.state = {
	// is recaptcha element rendered, it can only be rendered once
	rendered: false,
	currentWidth: 0,
	parentWidth: 0,
	}

	this.handleOnExpired = this.handleOnExpired.bind(this)
	this.handleOnError = this.handleOnError.bind(this)
	this.bindRef = this.bindRef.bind(this)
	this.renderRecaptcha = this.renderRecaptcha.bind(this)
	this.resetRecaptcha = this.resetRecaptcha.bind(this)
	}

	handleOnExpired() {
	this.props.onResponseChange()
	}

	handleOnError() {
	// Executed when recaptcha encounters an error (usually network
	// connectivity) and cannot continue until connectivity is restored.
	//
	// If the error callback is not provided, recaptcha will pop an alert which
	// is duplicated with our offline modal. So provide the callback and leave
	// it blank.
	}

	bindRef(ref) {
	this.ref = ref
	}

	renderRecaptcha() {
	if (!this.props.isRecaptchaLoaded \|\| this.state.rendered) {
	return
	}

	this.widgetId = grecaptcha.render(this.ref, {
	sitekey: GOOGLE_RECAPTCHA_SITE_KEY,

	size: 'normal',

	// executed when the recaptcha response expires (2 mins) and the user
	// needs to re-verify
	'expired-callback': this.handleOnExpired,

	'error-callback': this.handleOnError,

	// executed when the user passes the challenge. The g-recaptcha-response
	// token is passed to the callback
	callback: this.props.onResponseChange,
	})

	this.setState({rendered: true})
	this.setState({parentWidth: this.ref.parentNode.clientWidth})
	this.setState({currentWidth: this.ref.clientWidth})
	}

	resetRecaptcha() {
	grecaptcha.reset(this.widgetId)
	}

	componentDidMount() {
	this.renderRecaptcha()
	}

	componentDidUpdate(prevProps) {
	if (!prevProps.shouldResetRecaptcha && this.props.shouldResetRecaptcha) {
	this.resetRecaptcha()
	}
	this.renderRecaptcha()
	}

	render() {
	const style = {display: 'inline-block'}
	const {currentWidth, parentWidth} = this.state
	return (

	// Scale recaptcha size to fit its parant width for small screen size mobile.
	<div
	ref={this.bindRef}
	style={
	currentWidth !== 0 ? {
	...style,
	transform: `scale(${ currentWidth > parentWidth ? parentWidth / currentWidth : 1 })`,
	transformOrigin: 0,
	} : style
	}
	></div>
	)
	}
	}

	Recaptcha.propTypes = {
	// The response is given when user passes the challenge. Should send the
	// response along with form data to API to verify the user is not a robot.
	// See https://developers.google.com/recaptcha/docs/verify
	onResponseChange: PropTypes.func.isRequired,

	isRecaptchaLoaded: PropTypes.bool.isRequired,
	shouldResetRecaptcha: PropTypes.bool.isRequired,
	}

	export default Recaptcha