JSFiddle - React, Tailwind, and code Playground

HTML

<input type='text'>

<p></p>
<span></span>

CSS

span {
    color: red;
}

JavaScript

$('input').keyup(function() {
    var _val = $(this).val();


    function parseDay(val) {
        val = val.toLowerCase();
        var days = ['sunday', 'monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday'];
        for (var i = 0; i < days.length; i++)
            if (days[i].indexOf(val) == 0)
                return days[i];
    }
    
     $('span').text(parseDay(_val)); 
});