Validate using regular expressions in JavaScript

1.Date Validation:

const datePattern = /^\d{4}-\d{2}-\d{2}$/;

function isDateValid(date) {
  return datePattern.test(date);
}

// Example usage:
const validDate = "2023-11-07";
const invalidDate = "11/07/2023";

console.log(isDateValid(validDate));    // true
console.log(isDateValid(invalidDate));  // false

2.Time Validation

const timePattern = /^(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]$/;

function isTimeValid(time) {
  return timePattern.test(time);
}

// Example usage:
const validTime = "15:30";
const invalidTime = "25:00";

console.log(isTimeValid(validTime));    // true
console.log(isTimeValid(invalidTime));  // false

3.Email Validation:

const emailPattern = /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/;

function isEmailValid(email) {
  return emailPattern.test(email);
}

// Example usage:
const validEmail = "[e-mail]";
const invalidEmail = "invalid-email";

console.log(isEmailValid(validEmail));    // true
console.log(isEmailValid(invalidEmail));  // false

4.User name validation:

const usernamePattern = /^[a-zA-Z0-9_-]+$/;

function isUsernameValid(username) {
  return usernamePattern.test(username);
}

// Example usage:
const validUsername = "john_doe-123";
const invalidUsername = "user@name";

console.log(isUsernameValid(validUsername));    // true
console.log(isUsernameValid(invalidUsername));  // false