title: second argument applicationverifier must be an implementation of firebase.auth.applicationverifier
body: <p>second argument applicationverifier must be an implementation of firebase.auth.applicationverifier</p>
  
  <pre><code> .auth()
    .signInWithPhoneNumber(phoneNumber, appVerifier)
    .then(function(confirmationResult) {
      // SMS sent. Prompt user to type the code from the message, then sign the
      // user in with confirmationResult.confirm(code).
      window.confirmationResult = confirmationResult;
      //
      alert("SMS sent");
    })
    .catch(function(error) {
      // Error; SMS not sent
      // ...
      alert("Error ! SMS not sent");
    });
  
  
  
   initReCaptcha() {
  setTimeout(() =&gt; {
    let vm = this;
    window.recaptchaVerifier = new firebase.auth.RecaptchaVerifier(
      "recaptcha-container",
      {
        size: "invisible",
        callback: function(response) {
          // reCAPTCHA solved, allow signInWithPhoneNumber.
          // ...
        },
        "expired-callback": function() {
          // Response expired. Ask user to solve reCAPTCHA again.
          // ...
        }
      }
    );
    //
    this.appVerifier = window.recaptchaVerifier;
  }, 1000);
  }
  
  created() {
    this.initReCaptcha();
  }
  </code></pre>
  
  <p>i set app verifier as second argument but it generate error what should i do </p>