Vue/Vuelidate: Dynamically show required star (*) based on requiredIf - vue.js

Question

I'm creating a dynamic re-usable vue component that wraps a text input and includes the vuelidate validation stylings, etc.:
<template>
<div class="form-group" :class="{'form-group--error': validator.$error}">
<label>{{ label }}<span v-if="validator.$params.required">*</span></label>
<input type="text v-model="validator.$model" />
<div class="error" v-if="validator.$error && !validator.required">* This field is required</div>
</div>
<template>
<script>
export default {
name: "FormTextField",
props: ["validator", "label"]
}
</script>
(validator prop is $v from parent)
The problem I have is trying to show the <span>*</span> dynamically based on if the field is required. This currently works (v-if="validator.$params.required") as long as I only specify the required validator:
fieldName: {
required: required
}
Now, I need to instead declare my validation like this:
fieldName: {
required: requiredIf( ... )
}
The question is how to access the result of the requiredIf function? validator.$params.required will always be true since it's just checking if the param is there. And validator.required is the status of the validation, not the result of the requiredIf call to see whether it SHOULD be required or not.
Any suggestions on how I can show the required star dynamically based on vuelidate state?

Answer 1

Instead of validator.$params.required, check validator.required, which is only defined when there's a required or requiredIf validator rule applied. The value of validator.required is true when the field is missing, or false otherwise.
When the field is optional (has no required/requiredIf rule), the validator.required property does not exist, so we can't use v-if="!validator.required". Instead, explicitly compare validator.require to false:
<label>{{ label }}<span v-if="validator.required === false">*</span></label>
<div class="error" v-if="validator.$error && validator.required === false">* This field is required</div>
demo