Bugfixes. Documentation update.

dist/functions/server/handle-hmr.js

@@ -8,6 +8,7 @@ export default async function ({ req }) {
         ? global.BUNDLER_CTX_MAP?.find((m) => m.local_path == match.filePath)
         : undefined;
     let controller;
+    let heartbeat;
     const stream = new ReadableStream({
         start(c) {
             controller = c;
@@ -16,8 +17,17 @@ export default async function ({ req }) {
                 page_url: referer_url.href,
                 target_map,
             });
+            heartbeat = setInterval(() => {
+                try {
+                    c.enqueue(": keep-alive\n\n");
+                }
+                catch {
+                    clearInterval(heartbeat);
+                }
+            }, 5000);
         },
         cancel() {
+            clearInterval(heartbeat);
             const targetControllerIndex = global.HMR_CONTROLLERS.findIndex((c) => c.controller == controller);
             if (typeof targetControllerIndex == "number" &&
                 targetControllerIndex >= 0) {

dist/functions/server/web-pages/grab-web-page-hydration-script.js

@@ -19,6 +19,7 @@ export default async function (params) {
     script += `window.addEventListener("error", (e) => __bunext_show_error(e.message, e.filename ? e.filename + ":" + e.lineno + ":" + e.colno : "", e.error?.stack ?? ""));\n`;
     script += `window.addEventListener("unhandledrejection", (e) => __bunext_show_error(String(e.reason?.message ?? e.reason), "", e.reason?.stack ?? ""));\n\n`;
     script += `const hmr = new EventSource("/__hmr");\n`;
+    script += `window.BUNEXT_HMR = hmr;\n`;
     script += `window.addEventListener("beforeunload", () => hmr.close());\n`;
     script += `hmr.addEventListener("update", async (event) => {\n`;
     script += `    if (event?.data) {\n`;