Question

What is the difference between synchronous and asynchronous validation? Can you provide examples of when to use each?

Answer 1

Synchronous validation occurs during the execution of a program, blocking further actions until validation is complete. It’s best used when immediate feedback is necessary, such as form input validations where user mistakes can be corrected on-the-spot.

Example:

function validateInput(input) {

if (input === '') throw new Error('Invalid Input');

}

try {

validateInput('');

} catch (error) {

console.error(error);

}

Asynchronous validation, however, doesn’t block program execution and allows other operations to continue while validation is in progress. This is ideal for server-side validations or tasks that may take time, like checking database records.

Example:

async function validateUsername(username) {

const exists = await checkDatabase(username);

if (exists) throw new Error('Username Taken');

}

validateUsername('test').catch(console.error);