Using Vee-validate to disable button until form is filled out correctly

Question

I want to disable my submit button until my form is filled out correctly, this is what I have so far:

<form>
   <input type="text" class="form-control" v-validate="'required|email'" name="email" placeholder="Email" v-model="userCreate.userPrincipalName" />
   <span v-show="errors.has('email')">{{ errors.first('email') }}</span>
   <button v-if="errors.any()" disabled="disabled" class="btn btn-primary" v-on:click="sendInvite();" data-dismiss="modal" type="submit">Send Invite</button>
   <button v-else="errors.any()" class="btn btn-primary" v-on:click="sendInvite();" data-dismiss="modal" type="submit">Send Invite</button>
</form>

The above only prints an error message and disables my submit button after I've started inputting a value. I need it to be disabled from the start, before I start interacting with the input, so that I cannot send an empty string.

Another question is if there is a better way than using v-ifto do this?

EDIT:

 userCreate: {
        customerId: null,
        userPrincipalName: '',
        name: 'unknown',
        isAdmin: false,
        isGlobalAdmin: false,
        parkIds: []
    }

Answer 1

Probably simpliest way is to use ValidationObserver slot for a form. Like this:

<ValidationObserver v-slot="{ invalid }">
  <form @submit.prevent="submit">
    <InputWithValidation rules="required" v-model="first" :error-messages="errors" />
    <InputWithValidation rules="required" v-model="second" :error-messages="errors" />
    <v-btn :disabled="invalid">Submit</v-btn>
  </form>
</ValidationObserver>

More info - Validation Observer