fix(preloader): race condition on load + refactor

Author: wmertens

packages/qwik/src/core/preloader/bundle-graph.ts

@@ -1,5 +1,5 @@
 import { isBrowser } from '@builder.io/qwik/build';
-import { config, doc } from './constants';
+import { config, isJSRegex } from './constants';
 import { adjustProbabilities, bundles, log, shouldResetFactor, trigger } from './queue';
 import type { BundleGraph, BundleImport, ImportProbability } from './types';
 import { BundleImportState_None, BundleImportState_Alias } from './types';
@@ -8,15 +8,9 @@ export let base: string | undefined;
 export let graph: BundleGraph;
 
 const makeBundle = (name: string, deps?: ImportProbability[]) => {
-  const url = name.endsWith('.js')
-    ? doc
-      ? new URL(`${base}${name}`, doc.baseURI).toString()
-      : name
-    : null;
   return {
     $name$: name,
-    $url$: url,
-    $state$: url ? BundleImportState_None : BundleImportState_Alias,
+    $state$: isJSRegex.test(name) ? BundleImportState_None : BundleImportState_Alias,
     $deps$: shouldResetFactor ? deps?.map((d) => ({ ...d, $factor$: 1 })) : deps,
     $inverseProbability$: 1,
     $createdTs$: Date.now(),

packages/qwik/src/core/preloader/constants.ts

@@ -19,3 +19,5 @@ export const rel =
 
 // Global state
 export const loadStart = Date.now();
+
+export const isJSRegex = /\.[mc]?js$/;

packages/qwik/src/core/preloader/preloader.unit.ts

@@ -21,5 +21,5 @@ test('preloader script', () => {
    * dereference objects etc, but that actually results in worse compression
    */
   const compressed = compress(Buffer.from(preLoader), { mode: 1, quality: 11 });
-  expect([compressed.length, preLoader.length]).toEqual([1785, 5298]);
+  expect([compressed.length, preLoader.length]).toEqual([1785, 5285]);
 });

packages/qwik/src/core/preloader/queue.ts

@@ -121,7 +121,8 @@ const preloadOne = (bundle: BundleImport) => {
     );
 
   const link = doc.createElement('link');
-  link.href = bundle.$url$!;
+  // Only bundles with state none are js bundles
+  link.href = new URL(`${base}${bundle.$name$}`, doc.baseURI).toString();
   link.rel = rel;
   // Needed when rel is 'preload'
   link.as = 'script';
@@ -208,7 +209,7 @@ export const handleBundle = (name: string, inverseProbability: number) => {
 };
 
 export const preload = (name: string | (number | string)[], probability?: number) => {
-  if (base == null || !name.length) {
+  if (!name?.length) {
     return;
   }
 

packages/qwik/src/core/preloader/types.ts

@@ -12,7 +12,6 @@ export type BundleInfo = {
 
 export type BundleImport = BundleInfo & {
   $name$: string;
-  $url$: string | null;
   $state$: number;
   $createdTs$: number;
   $waitedMs$: number;