Fixes: dynamic import() to load ESM-only dependency

Author: HeyyyNeo

.changeset/curly-balloons-fry.md

@@ -0,0 +1,5 @@
+---
+"@react-router/dev": patch
+---
+
+Use a dynamic `import()` to load ESM-only `p-map` dependency to avoid issues on Node 20.18 and below

contributors.yml

@@ -452,3 +452,4 @@
 - zeromask1337
 - zheng-chuang
 - zxTomw
+- HeyyyNeo

packages/react-router-dev/vite/plugin.ts

@@ -36,7 +36,6 @@ import pick from "lodash/pick";
 import jsesc from "jsesc";
 import colors from "picocolors";
 import kebabCase from "lodash/kebabCase";
-import pMap from "p-map";
 
 import * as Typegen from "../typegen";
 import type { RouteManifestEntry, RouteManifest } from "../config/routes";
@@ -2815,7 +2814,8 @@ async function handlePrerender(
     concurrency = prerender.unstable_concurrency ?? 1;
   }
 
-  await pMap(build.prerender, prerenderSinglePath, { concurrency });
+  const pMap = await import("p-map");
+  await pMap.default(build.prerender, prerenderSinglePath, { concurrency });
 }
 
 function getStaticPrerenderPaths(routes: DataRouteObject[]) {