How can I implement async validation in Vue with TypeScript?

How can I implement async validation in Vue with TypeScript?

You can use the async keyword in your validation methods and leverage Vue's reactivity. Would you like a code example?

Yes, please provide a code example.

Sure! Here's a simple example:

import { ref } from 'vue';

const email = ref('');
const emailError = ref('');

const validateEmail = async () => {
  emailError.value = '';
  if (!email.value.includes('@')) {
    emailError.value = 'Invalid email address';
    return;
  }
  // Simulate async validation
  const isTaken = await checkEmailInDatabase(email.value);
  if (isTaken) {
    emailError.value = 'Email is already taken';
  }
};

const checkEmailInDatabase = async (email: string) => {
  // Simulate an API call
  return new Promise<boolean>((resolve) => {
    setTimeout(() => resolve(email === '[email protected]'), 1000);
  });
};

This code checks if the email is valid and simulates an async call to check if it's already taken.

That looks great! How do I trigger the validation when the user types?

You can use the @input event on your input field to call the validateEmail function. Here's how:

<input v-model="email" @input="validateEmail" />
<span v-if="emailError">{{ emailError }}</span>