Fix broken BigInt64Array unsupported message on old Safari

frontend/src/main.ts

@@ -4,11 +4,30 @@
 import "reflect-metadata";
 import { createApp } from "vue";
 
+import { stripIndents } from "@/utility-functions/strip-indents";
 import { initWasm } from "@/wasm-communication/editor";
 
 import App from "@/App.vue";
 
 (async (): Promise<void> => {
+	if (!("BigUint64Array" in window)) {
+		const body = document.body;
+		const message = stripIndents`
+			<style>
+			h2, p, a {
+				text-align: center;
+				color: white;
+			}
+			</style>
+			<h2>This browser is too old</h2>
+			<p>Please upgrade to a modern web browser such as the latest Firefox, Chrome, Edge, or Safari version 15 or later.</p>
+			<p>(The <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt64Array#browser_compatibility" target="_blank"><code>BigInt64Array</code></a>
+			JavaScript API must be supported by the browser for Graphite to function.)</p>
+			`;
+		body.innerHTML = message + body.innerHTML;
+		return;
+	}
+
 	// Initialize the WASM module for the editor backend
 	await initWasm();