React Native

import { useEffect, useRef, useState } from 'react'
import { SafeAreaProvider, SafeAreaView } from 'react-native-safe-area-context'
import { WebView, WebViewMessageEvent } from 'react-native-webview'

const sdkMobileServer = 'https://sdk-mobile.cert.zerohash.com/'
const zeroHashAppsURL = 'https://web-sdk.cert.zerohash.com'

const App = () => {
  const webViewRef = useRef<WebView>(null)
  const [token, setToken] = useState<string>('<JWT_TOKEN_HERE>')

  useEffect(() => {
    fetchJwt()
  }, [])

  // Fetch JWT token from server
  const fetchJwt = async () => {
    const jwtPayload = {
      participant_code: '{PARTICIPANT_CODE}',
      permissions: [
        'crypto-buy',
        'crypto-sell',
        'crypto-withdrawals',
        'fiat-deposits',
        'fiat-withdrawals',
      ],
    }
    try {
      const response = await fetch(`<API_URL_TO_FETCH_TOKEN>`, {
        method: 'POST',
        body: JSON.stringify(jwtPayload),
      })
      const parsedResponse = await response.json()
      setToken(parsedResponse.message.token)
    } catch (e) {
      console.error('could not fetch jwt')
    }
  }

  // Open modal using injected JS script in webview
  const openModal = () => {
    webViewRef.current?.injectJavaScript(
      `window.postMessage({ "type": "OPEN_MODAL", "payload": { "appIdentifier": "crypto-buy"}});true;`
    )
  }

  const handleMessage = (event: WebViewMessageEvent) => {
    try {
      // Parse message from webview event data checking nativeEvent field
      const parsedMessage = JSON.parse(event.nativeEvent.data)
      console.log('Received message:', parsedMessage)
      if (parsedMessage.type === 'SDK_MOBILE_READY') {
        console.log('SDK is ready, opening modal...')
        openModal()
      }
      // Handle webview events
      // Your code here...
    } catch (e) {
      alert(
        `could not parse message: ${JSON.stringify(event.nativeEvent.data)}`
      )
    }
  }

  return (
    <SafeAreaProvider>
      <SafeAreaView>
        <WebView
          allowsInlineMediaPlayback={true}
          ref={webViewRef}
          onMessage={handleMessage}
          source={{
            uri: generateURL(),
          }}
          onNavigationStateChange={(event) => {
            if (!event.url.startsWith(sdkMobileServer)) {
              webViewRef.current.stopLoading()
              Linking.openURL(event.url)
            }
          }}
        />
      </SafeAreaView>
    </SafeAreaProvider>
  )
}

export default App