JSFiddle - React, Tailwind, and code Playground
HTML
<input id="myInput" type="submit" value="This is a test"/>
CSS
input{
white-space: normal;
}
JavaScript
var inputValue = $("#myInput").val();
var inputValues = inputValue.split(" ");
var longestValue = inputValues.reduce(function (a, b) { return a.length > b.length ? a : b; });
$("#myInput").val(longestValue);
var length = $("#myInput").outerWidth();
$("#myInput").css("width", length);
$("#myInput").val(inputValue);