form.vue

<template>
  <form @submit.prevent="action">
    <label>Your name:
      <input name="name" required>
    </label>
    <button :disabled="disabled">
      Action
    </button>
  </form>
</template>

<script>
import { ref } from 'vue'

export default {
  name: 'componentName',
  const disabled = ref(false)
  setup() {
    const action = async() => {
      disabled.value = true // disable btn to re-submits
      // show loading after form is submitted
      try {
        // your api call
        disabled.value = false // active btn before submit
        // hide loading after form is submitted
      } catch (error) {
        disabled.value = false
        // hide loading after form is submitted
        // catch your error
      }
    }
    return {
      action,
      disabled
    }
  }
}
</script>

<style scoped></style>

i think you should return login or rename login method to action

@khofaai 👍