JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://sinonjs.org/releases/sinon-1.7.3.js"></script>

JavaScript

var $window = $(window);

sinon.stub($window, 'width').returns(900);

// "900"
$('body').append('<div>Stubbed window width: ' + $window.width() + '</div>');

// real window width
$('body').append('<div>Window width read from fresh jQuery object (not affected by the stub): ' + $(window).width() + '</div>');