https://app.gyomanager.com/vendor/adminlte3/gyo/js/toggler.js

1let passwordToggler = document.querySelector('.toggle-password');
2let passwordInput   = document.querySelector('#password');
3let icon            = passwordToggler.querySelector('.fas');
4  
5passwordToggler.addEventListener('click', (e)=>{
6  passwordInput.type = (passwordInput.type == 'password') ? 'text' : 'password';
7  if (icon.classList.contains('fa-eye')) {
8    icon.classList.remove('fa-eye');
9    icon.classList.add('fa-eye-slash');
10  } else {
11    icon.classList.add('fa-eye');
12    icon.classList.remove('fa-eye-slash');
13  }
14});