From e1b1ead661b46a5aaf94fa7afefaa5b544ae34e0 Mon Sep 17 00:00:00 2001
From: Christoph Reiter <reiter.christoph@gmail.com>
Date: Tue, 21 Apr 2020 11:47:54 +0200
Subject: [PATCH] Add browser-check.js
This should be used by every app, so move it here to avoid duplication.
---
packages/common/misc/browser-check.js | 191 ++++++++++++++++++++++++++
1 file changed, 191 insertions(+)
create mode 100644 packages/common/misc/browser-check.js
diff --git a/packages/common/misc/browser-check.js b/packages/common/misc/browser-check.js
new file mode 100644
index 00000000..171e1044
--- /dev/null
+++ b/packages/common/misc/browser-check.js
@@ -0,0 +1,191 @@
+/* eslint-disable */
+
+/*
+This file is self contained and does various runtime checks to detect if teh current browser
+is supported. In case it isn't it will replace the whole(!) page with an error message.
+
+Example usage:
+ <script src="browser-check.js" defer></script>
+ <noscript>Diese Applikation benötigt Javascript / This application requires Javascript</noscript>
+*/
+
+
+(function () {
+
+// https://caniuse.com/#feat=es6
+function supportsES6() {
+ if (typeof Symbol == "undefined")
+ return false;
+
+ try {
+ eval("class Foo {}");
+ eval("var bar = (x) => x+1");
+ } catch (e) {
+ console.log(e);
+ return false;
+ }
+
+ return true;
+}
+
+// https://caniuse.com/#feat=es6-module-dynamic-import
+function supportsDynamicImport() {
+ try {
+ new Function('import("")');
+ return true;
+ } catch (err) {
+ return false;
+ }
+}
+
+// https://caniuse.com/#feat=shadowdomv1
+function supportsShadowDOM() {
+ return (typeof Element != "undefined" && 'attachShadow' in Element.prototype && 'getRootNode' in Element.prototype);
+}
+
+// https://caniuse.com/#feat=custom-elementsv1
+function supportsCustomElements() {
+ return !!window.customElements;
+}
+
+// https://caniuse.com/#feat=async-functions
+function supportsAsyncAwait() {
+ try {
+ eval('async () => {}');
+ } catch (e) {
+ return false;
+ }
+ return true;
+}
+
+// https://caniuse.com/#feat=mdn-javascript_statements_import_meta
+function supportsImportMeta() {
+ // TODO: sadly no idea how to test this..
+ return true;
+}
+
+// Eval can be disabled through https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP
+function supportsEval() {
+ try {
+ eval('');
+ } catch (e) {
+ return false;
+ }
+ return true;
+}
+
+function isBrowserSupported() {
+ if (!supportsEval()) {
+ console.log("Eval support disabled, skipping browser feature detection.");
+ return true;
+ }
+
+ if (!supportsES6()) {
+ console.log("ES6 not supported");
+ return false;
+ }
+
+ if (!supportsDynamicImport()) {
+ console.log("Dynamic imports not supported");
+ return false;
+ }
+
+ if (!supportsShadowDOM()) {
+ console.log("Shadow DOM not supported");
+ return false;
+ }
+
+ if (!supportsCustomElements()) {
+ console.log("Custom Elements not supported");
+ return false;
+ }
+
+ if (!supportsAsyncAwait()) {
+ console.log("Async Await not supported");
+ return false;
+ }
+
+ if (!supportsImportMeta()) {
+ console.log("import.meta not supported");
+ return false;
+ }
+
+ return true;
+}
+
+var MultiString = function(f) {
+ return f.toString().split('\n').slice(1, -1).join('\n');
+};
+
+var ms = MultiString(function() {/**
+<style>
+ #unsupported .overlay {
+ font-family: sans-serif;
+ font-size: 0.9em;
+ line-height: 1.5em;
+ position: fixed;
+ width: 100%;
+ height: 100%;
+ top: 0;
+ left: 0;
+ right: 0;
+ bottom: 0;
+ background-color: #fafafa;
+ color: #333;
+ z-index: 1001;
+ }
+ #unsupported .content{
+ position: absolute;
+ top: 50%;
+ left: 0;
+ text-align: center;
+ width: 80%;
+ left: 10%;
+ -ms-transform: translateY(-50%);
+ transform: translateY(-50%);
+ }
+ #unsupported .separator {
+ letter-spacing: 0.3em;
+ margin: 2em 0;
+ }
+ #unsupported .footer {
+ position: fixed;
+ top: 0.5em;
+ line-height: 2em;
+ width: 100%;
+ text-align: center;
+ }
+</style>
+<div id="unsupported">
+ <div class="overlay">
+ <div class="content">
+ <h2>Ihr Browser wird leider nicht mehr unterstützt</h2>
+ <p>
+ Diese Applikation benötigt Funktionen, die von Ihrem aktuellen Browser noch nicht bereitgestellt werden.
+ Bitte probieren Sie es mit einem anderen Browser oder aktualisieren Sie Ihren aktuellen.
+ </p>
+ <h3 class="separator">ðŸ™ðŸ™ðŸ™ðŸ™ðŸ™ðŸ™ðŸ™ðŸ™ðŸ™ðŸ™ðŸ™ðŸ™</h3>
+ <h2>Your browser is sadly no longer supported</h2>
+ <p>
+ This application requires features that are not yet provided by your current browser.
+ Please try to use a different browser or update your current one.
+ </p>
+ </div>
+ <div class="footer">
+ IT Support: <a href="mailto:it-support@tugraz.at">it-support@tugraz.at</a>
+ <br>
+ <a href="https://datenschutz.tugraz.at/erklaerung/" target="_blank" rel="noopener">Datenschutzerklärung / Privacy Policy</a>
+ </div>
+ </div>
+</div>
+**/});
+
+function main() {
+ if (!isBrowserSupported()) {
+ document.body.innerHTML = ms;
+ }
+}
+
+main();
+
+})();
--
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