I'm trying to imitate Bootstrap form validation styling with Vue and Vee-validate.

In order to have that Boostrap validation error message, when there's a validation error, the input itself must have is-invalid class presents. And in addition, the error message element must have invalid-feedback class, of course.

I'm struggling to add is-invalid class to the input when there's a validation error.

In Vee-validate 3, I was able to control the input element's classes with this guide. But it seems to be deprecated.

This is a code sandbox that you can play with. Nothing extra-ordinary, just straight out of Veevalidate example.

<template>
  <div id="app">
    <Form @submit="onSubmit">
      <Field name="email" type="email" :rules="validateEmail" />
      <ErrorMessage  name="email" />
      <button >Sign up</button>
    </Form>
  </div>
</template>

<script>
  import {
    Form,
    Field,
    ErrorMessage
  } from "vee-validate";

  export default {
    components: {
      Form,
      Field,
      ErrorMessage,
    },
    methods: {
      onSubmit(values) {
        console.log(values, null, 2);
      },
      validateEmail(value) {
        // if the field is empty
        if (!value) {
          return "This field is required";
        }

        // if the field is not a valid email
        const regex = /^[A-Z0-9._% -] @[A-Z0-9.-] \.[A-Z]{2,4}$/i;
        if (!regex.test(value)) {
          return "This field must be a valid email";
        }

        // All is good
        return true;
      },
    },
  };
</script>

<style>
  span {
    display: block;
    margin: 10px 0;
  }
</style>

Versions

1. "vee-validate": "^4.5.11",
2. "vue": "^3.2.33",

CodePudding user response：

You can render more complex fields, by utilizing the scoped slots of the <Field />-component.

If you replace your Field-component with the following, it should work as expected:

<Field name="email" :rules="validateEmail" v-slot="{ field, errors }">
  <input v-bind="field" type="email" : />
</Field>