Inline startTransitionImpl to avoid .d.ts issues with skipLibCheck:false

.changeset/tsc-skiplibcheck-react17.md

@@ -0,0 +1,6 @@
+---
+"react-router": patch
+"react-router-dom": patch
+---
+
+Fix `tsc --skipLibCheck:false` issues on React 17

packages/react-router-dom/index.tsx

@@ -27,7 +27,6 @@ import {
   UNSAFE_NavigationContext as NavigationContext,
   UNSAFE_RouteContext as RouteContext,
   UNSAFE_mapRouteProperties as mapRouteProperties,
-  UNSAFE_startTransitionImpl as startTransitionImpl,
   UNSAFE_useRouteId as useRouteId,
 } from "react-router";
 import type {
@@ -297,6 +296,30 @@ function deserializeErrors(
 //#region Components
 ////////////////////////////////////////////////////////////////////////////////
 
+/**
+  Webpack + React 17 fails to compile on any of the following because webpack
+  complains that `startTransition` doesn't exist in `React`:
+  * import { startTransition } from "react"
+  * import * as React from from "react";
+    "startTransition" in React ? React.startTransition(() => setState()) : setState()
+  * import * as React from from "react";
+    "startTransition" in React ? React["startTransition"](() => setState()) : setState()
+
+  Moving it to a constant such as the following solves the Webpack/React 17 issue:
+  * import * as React from from "react";
+    const START_TRANSITION = "startTransition";
+    START_TRANSITION in React ? React[START_TRANSITION](() => setState()) : setState()
+
+  However, that introduces webpack/terser minification issues in production builds
+  in React 18 where minification/obfuscation ends up removing the call of
+  React.startTransition entirely from the first half of the ternary.  Grabbing
+  this exported reference once up front resolves that issue.
+
+  See https://github.com/remix-run/react-router/issues/10579
+*/
+const START_TRANSITION = "startTransition";
+const startTransitionImpl = React[START_TRANSITION];
+
 export interface BrowserRouterProps {
   basename?: string;
   children?: React.ReactNode;

packages/react-router/index.ts

@@ -43,7 +43,6 @@ import {
   UNSAFE_warning as warning,
 } from "@remix-run/router";
 
-import startTransitionImpl from "./lib/polyfills/start-transition";
 import type {
   AwaitProps,
   MemoryRouterProps,
@@ -304,5 +303,4 @@ export {
   mapRouteProperties as UNSAFE_mapRouteProperties,
   useRouteId as UNSAFE_useRouteId,
   useRoutesImpl as UNSAFE_useRoutesImpl,
-  startTransitionImpl as UNSAFE_startTransitionImpl,
 };

packages/react-router/lib/components.tsx

@@ -22,7 +22,6 @@ import {
   UNSAFE_getPathContributingMatches as getPathContributingMatches,
 } from "@remix-run/router";
 
-import startTransitionImpl from "./polyfills/start-transition";
 import type {
   DataRouteObject,
   IndexRouteObject,
@@ -60,6 +59,30 @@ export interface RouterProviderProps {
   future?: FutureConfig;
 }
 
+/**
+  Webpack + React 17 fails to compile on any of the following because webpack
+  complains that `startTransition` doesn't exist in `React`:
+  * import { startTransition } from "react"
+  * import * as React from from "react";
+    "startTransition" in React ? React.startTransition(() => setState()) : setState()
+  * import * as React from from "react";
+    "startTransition" in React ? React["startTransition"](() => setState()) : setState()
+
+  Moving it to a constant such as the following solves the Webpack/React 17 issue:
+  * import * as React from from "react";
+    const START_TRANSITION = "startTransition";
+    START_TRANSITION in React ? React[START_TRANSITION](() => setState()) : setState()
+
+  However, that introduces webpack/terser minification issues in production builds
+  in React 18 where minification/obfuscation ends up removing the call of
+  React.startTransition entirely from the first half of the ternary.  Grabbing
+  this exported reference once up front resolves that issue.
+
+  See https://github.com/remix-run/react-router/issues/10579
+*/
+const START_TRANSITION = "startTransition";
+const startTransitionImpl = React[START_TRANSITION];
+
 /**
  * Given a Remix Router instance, render the appropriate UI
  */