Cannot read property 'style' of null - Google Sign-In Button

Question

I'm trying to implement Google sign in for my website. The Sign-In button shows up correctly and signs-people in well initially. My problem occurs when I log out after having used the website and try to move to the Sign-In page (I'm using React, so it's all one page). I use the exact same function to render the Sign-In page but it gives me a "cb=gapi.loaded_0:249 Uncaught TypeError: Cannot read property 'style' of null". The error in gapi occurs here (at least I think):

 a.El;window.document.getElementById((c?"not_signed_in":"connected"

This is how I initially add the Sign-In button to be rendered:

elements.push(h('div.g-signin2',{'data-onsuccess': 'onSignIn'}))
        return h('div.page_content',elements)

which I later render with a ReactDOM.render call.

Here's how I handle SignOut and SignIn:

function signOut() {
    var auth2 = gapi.auth2.getAuthInstance();
    auth2.signOut().then(function () {
      // console.log('User signed out.');
      signedin = false;
      auth2 = null;
      renderPage()
    });
  }

var google_idtoken;
var signedin = false;

// set auth2 to null to indicate that google api hasn't been loaded yet
var auth2 = null;

function onSignIn(googleUser) {
    auth2 = gapi.auth2.getAuthInstance({
        client_id: 'ClientID.apps.googleusercontent.com'
    });
    google_idtoken = googleUser.getAuthResponse().id_token;
    wrongemail = true;
  // if(auth2 != null && auth2.isSignedIn.get() == true){

    if ((((auth2.currentUser.get()).getBasicProfile()).getEmail()).split("@").pop() == 'domain.com'){
        signedin = true
        wrongemail = false
    }
    updateSources()
    // renderPage()
}

Answer 1

I had a similar problem though I'm not sure it's exactly related to your issue. I had added the button in the html as:

<div id="gdbtn" class="g-signin2" data-onsuccess="onSignIn"></div>

But I wanted to customize the rendering of the button according to Google's instructions so I added the platform script as:

<script src="https://apis.google.com/js/platform.js?onload=renderGDriveButton"></script>

With the following onload function:

function renderGDriveButton() {
  gapi.signin2.render('gdbtn', { 
    'height': 50
  });
}

I got the same error you did: "Uncaught TypeError: Cannot read property 'style' of null". My problem was that I included the attributes: class="g-signin2" data-onsuccess="onSignIn" Once I took those attributes out and added the button as:

<div id="gdbtn"></div>

Then the error went away. Seems very similar to your issue. You might try adding the button through an onload function. Just a thought. You can check out the docs at: https://developers.google.com/identity/sign-in/web/build-button