JSFiddle - React, Tailwind, and code Playground

JavaScript

function validatePass(ev) {
	var pswd = this.value,
  		$pswdField = jQuery('#length'),
      VALID_CLS = 'valid fa-check',
      INVALID_CLS = 'invalid fa-times';
	if (pswd.length < 8) {
			$pswdField.removeClass(VALID_CLS).addClass(INVALID_CLS);
		} else {
			$pswdField.removeClass(INVALID_CLS).addClass(VALID_CLS);
		}
}