JSFiddle - React, Tailwind, and code Playground

HTML

<input class="auto" type="text">

JavaScript

$('.auto').keyup(function() {
    var $this = $(this),
        value = $this.val().toLowerCase();

    $this.val(value.replace(/^(.)|\s(.)/g, function(a) {
        return a.toUpperCase();
    }));
});