Form Validation     

<template>
  <div>
    <q-input
      v-model="form.email"
      @blur="$v.form.email.$touch"
      @keyup.enter="submit"
      :error="$v.form.email.$error"
    />

    <q-btn color="primary" @click="submit">Submit</q-btn>
  </div>
</template>

<script>
import { required, email } from 'vuelidate/lib/validators'
import { Toast } from 'quasar'

export default {
  data () {
    return {
      form: {
        email: ''
      }
    }
  },
  validations: {
    form: {
      email: { required, email  }
    }
  },
  methods: {
    submit () {
      this.$v.form.$touch()

      if (this.$v.form.$error) {
        Toast.create('Please review fields again.')
        return
      }

      // ...
    }
  }
}
</script>