text: /* Copyright (c) 2015-present, salesforce.com, inc. All rights reserved */
  /* Licensed under BSD 3-Clause - see LICENSE.txt or git.io/sfdc-license */
  
  /* eslint-disable import/no-mutable-exports */
  /* global XMLHttpRequest, window */
  
  // This function does an "AJAX" request to warn users on how to setup their icon path.
  import warning from 'warning';
  
  let urlExists = function() {};
  
  if (process.env.NODE_ENV !== 'production') {
  	const hasWarned = {};
  	let hasExecuted;
  
  	const warn = (control, url, comment) => (res) => {
  		hasExecuted = true;
  		if (res.status === 404) {
  			const additionalComment = comment ? ` ${comment}` : '';
  			/* eslint-disable max-len */
  			warning(
  				!url,
  				`The icon asset was not found at ${url}. Make sure the path to the icon asset is correct. You can set the icon path by importing the IconSettings component, \`<IconSettings iconPath=[/assets/icons]>\` from \`components/iconSettings\`, and wrap that component around your entire app or around individual components using icons. If you are using the \`<Icon>\` component, you can also pass the url to \`this.props.path\`.${additionalComment}`
  			);
  			/* eslint-enable max-len */
  			hasWarned[`${control}-path`] = !!url;
  		}
  	};
  
  	const shouldWarn = (control) =>
  		!hasExecuted &&
  		!hasWarned[`${control}-path`] &&
  		typeof window !== 'undefined' &&
  		process.env.NODE_ENV !== 'test';
  
  	if (typeof fetch === 'function') {
  		urlExists = function(control, url, comment) {
  			if (shouldWarn(control)) {
  				fetch(url).then(warn(control, url, comment));
  			}
  		};
  	} else {
  		// Using XMLHttpRequest can cause problems in non-browser environments. This should be completely removed in production environment and should not execute in a testing environment.
  		urlExists = function(control, url, comment) {
  			if (shouldWarn(control) && XMLHttpRequest) {
  				const http = new XMLHttpRequest();
  				http.open('GET', url, false);
  				http.send();
  				warn(control, url, comment)(http);
  			}
  		};
  	}
  }
  
  export default urlExists;
  