cache getRouteModuleExports calls

.changeset/rude-meals-move.md

@@ -0,0 +1,5 @@
+---
+"@remix-run/dev": patch
+---
+
+cache getRouteModuleExports calls to significantly speed up build and HMR rebuild times

packages/remix-dev/compiler/compiler.ts

@@ -107,6 +107,7 @@ export let create = async (ctx: Context): Promise<Compiler> => {
       config: ctx.config,
       metafile,
       hmr,
+      fileWatchCache: ctx.fileWatchCache,
     });
     refs.manifestChannel.ok(manifest);
     options.onManifest?.(manifest);

packages/remix-dev/compiler/js/plugins/routes.ts

@@ -1,3 +1,4 @@
+import * as path from "node:path";
 import type esbuild from "esbuild";
 
 import type { RemixConfig } from "../../../config";
@@ -22,7 +23,7 @@ const browserSafeRouteExports: { [name: string]: boolean } = {
  * that re-export only the route module exports that are safe for the browser.
  */
 export function browserRouteModulesPlugin(
-  { config }: Context,
+  { config, fileWatchCache }: Context,
   suffixMatcher: RegExp
 ): esbuild.Plugin {
   return {
@@ -54,7 +55,22 @@ export function browserRouteModulesPlugin(
           try {
             invariant(route, `Cannot get route by path: ${args.path}`);
 
-            theExports = (await getRouteModuleExports(config, route.id)).filter(
+            let cacheKey = `module-exports:${route.id}`;
+            let { cacheValue: sourceExports } = await fileWatchCache.getOrSet(
+              cacheKey,
+              async () => {
+                let file = path.resolve(
+                  config.appDirectory,
+                  config.routes[route!.id].file
+                );
+                return {
+                  cacheValue: await getRouteModuleExports(config, route!.id),
+                  fileDependencies: new Set([file]),
+                };
+              }
+            );
+
+            theExports = sourceExports.filter(
               (ex) => !!browserSafeRouteExports[ex]
             );
           } catch (error: any) {

packages/remix-dev/compiler/manifest.ts

@@ -7,17 +7,20 @@ import invariant from "../invariant";
 import { type Manifest } from "../manifest";
 import { getRouteModuleExports } from "./utils/routeExports";
 import { getHash } from "./utils/crypto";
+import { type FileWatchCache } from "./fileWatchCache";
 
 type Route = RemixConfig["routes"][string];
 
 export async function create({
   config,
   metafile,
   hmr,
+  fileWatchCache,
 }: {
   config: RemixConfig;
   metafile: esbuild.Metafile;
   hmr?: Manifest["hmr"];
+  fileWatchCache: FileWatchCache;
 }): Promise<Manifest> {
   function resolveUrl(outputPath: string): string {
     return createUrl(
@@ -70,7 +73,21 @@ export async function create({
         `Cannot get route(s) for entry point ${output.entryPoint}`
       );
       for (let route of groupedRoute) {
-        let sourceExports = await getRouteModuleExports(config, route.id);
+        let cacheKey = `module-exports:${route.id}`;
+        let { cacheValue: sourceExports } = await fileWatchCache.getOrSet(
+          cacheKey,
+          async () => {
+            let file = path.resolve(
+              config.appDirectory,
+              config.routes[route.id].file
+            );
+            return {
+              cacheValue: await getRouteModuleExports(config, route.id),
+              fileDependencies: new Set([file]),
+            };
+          }
+        );
+
         routes[route.id] = {
           id: route.id,
           parentId: route.parentId,

packages/remix-dev/devServer_unstable/hdr.ts

@@ -52,7 +52,24 @@ export let detectLoaderChanges = async (
             let file = args.path.replace(filter, "");
             let route = routesByFile.get(file);
             invariant(route, `Cannot get route by path: ${args.path}`);
-            let theExports = await getRouteModuleExports(ctx.config, route.id);
+            let cacheKey = `module-exports:${route.id}`;
+            let { cacheValue: theExports } = await ctx.fileWatchCache.getOrSet(
+              cacheKey,
+              async () => {
+                let file = path.resolve(
+                  ctx.config.appDirectory,
+                  ctx.config.routes[route!.id].file
+                );
+                return {
+                  cacheValue: await getRouteModuleExports(
+                    ctx.config,
+                    route!.id
+                  ),
+                  fileDependencies: new Set([file]),
+                };
+              }
+            );
+
             let contents = "module.exports = {};";
             if (theExports.includes("loader")) {
               contents = `export { loader } from ${JSON.stringify(