How can I create custom validation rules in Vuelidate for Vue.js?

How can I create custom validation rules in Vuelidate for Vue.js?

To create custom validation rules in Vuelidate, you can define a function that returns a validation object. For example, you can create a rule to check if a value is an even number.

Can you show me an example of such a custom rule?

Sure! Here's a simple example:

const isEven = value => value % 2 === 0;

export const validations = {
  numberField: {
    isEven: { validator: isEven, message: 'The number must be even.' }
  }
};

How do I use this validation in my Vue component?

You can use it in your component like this:

import { validations } from './validations';

export default {
  validations,
  data() {
    return { numberField: null };
  }
};

What if I want to combine multiple rules?

You can combine multiple rules by returning an object with all the validators. For example:

const isEven = value => value % 2 === 0;
const isPositive = value => value > 0;

export const validations = {
  numberField: {
    isEven: { validator: isEven, message: 'Must be even.' },
    isPositive: { validator: isPositive, message: 'Must be positive.' }
  }
};