title: How can i use cloud function with app in Firebase
body: <p>I wrote a function for verify idToken. My app in localHost and function deployed in Firebase, works normaly. But when i do <code>yarn build</code> and deploy of my React application  in Firebase, it doesn't work. What appears is the html of the index file of the build folder on the screen, when I click on the component that calls the function. In the package.json file, I wrote the proxy, with a function path in Firebase, and in component, I call the function with <code>axios.post (...)</code>. Should I fix something to make it work right after deploying?</p>
  
  <p>in my package.json of src i have:</p>
  
  <pre><code>"proxy": "https://us-central1-teste.cloudfunctions.net/",
  </code></pre>
  
  <p>in my component i have: </p>
  
  <pre><code>const user = yield auth.currentUser
      const {ra} = user
      const datas = yield new Promise(resolve =&gt; {
          resolve(axios.post('/auth?token='+ra)) 
      })
  if (datas.data === user.uid){
         ...
      }else{
          ...
      } 
  </code></pre>
  
  <p>in my cloud function i have:</p>
  
  <pre><code>const functions = require('firebase-functions')
  const admin = require('firebase-admin')
  admin.initializeApp(functions.config().firebase)
  
  exports.auth = functions.https.onRequest((request, response) =&gt; {   
  const idToken = request.query.token
  admin.auth().verifyIdToken(idToken)
  .then( decodedToken =&gt; {
      response.send(decodedToken.uid)  
      return 
  }).catch( error =&gt; {
      response.send(error.errorInfo.code)
      return
  })  
  })
  </code></pre>