Firebase displayName返回为NULL

Question

I am confused as to why when trying to output the display name it returns as NULL yet when I sign up for an account and console.log the displayName it shows my input?

I added a new field:

<input class="mdl-textfield__input" style="display:inline;width:auto;" type="text" id="displayName" name="displayName" placeholder="displayName"/>

Inside of the firebase.auth().createUserWithEmailAndPassword(email, password).catch(function(error) { function I did a console.log against displayName and it output when the field where submitted and created the user in the DB, but when outputting the displayName is returns as NULL

firebase.auth().onAuthStateChanged(function(user) {
        // [START_EXCLUDE silent]
        document.getElementById('quickstart-verify-email').disabled = true;
        // [END_EXCLUDE]
        if (user) {
          // User is signed in.
          var displayName = user.displayName;

Im just doing a simple text output on the users details like so:

document.getElementById('quickstart-account-details').textContent = JSON.stringify(user, null, '  ');

Answer 1

This is probably because you are executing

document.getElementById('quickstart-account-details').textContent = JSON.stringify(user, null, ' ');

before user is populated.

If so, try executing the above code inside the if (user) {} block.