@salesforce/design-system-react/utilities/warning/url-exists.js

Salesforce Lightning Design System for React

/* 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 urlExistsFunction() {};

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 urlExistsFunction(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 urlExistsFunction(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;