From 1497ab3a5864b9fd951497ec2e077fa4c8e10b73 Mon Sep 17 00:00:00 2001
From: Jacob Ebey <jacob.ebey@live.com>
Date: Mon, 8 Aug 2022 14:56:01 -0700
Subject: [PATCH] chore: add subscribe method to transition manager (#3964)

chore: update RemixEntry to use new subscribe method
---
 .changeset/slow-apples-pretend.md             |  5 +++
 .../remix-react/__tests__/transition-test.tsx |  4 +--
 packages/remix-react/components.tsx           | 34 ++++++++++++-------
 packages/remix-react/transition.ts            | 19 +++++++++--
 4 files changed, 45 insertions(+), 17 deletions(-)
 create mode 100644 .changeset/slow-apples-pretend.md

diff --git a/.changeset/slow-apples-pretend.md b/.changeset/slow-apples-pretend.md
new file mode 100644
index 00000000000..7547330d377
--- /dev/null
+++ b/.changeset/slow-apples-pretend.md
@@ -0,0 +1,5 @@
+---
+"@remix-run/react": patch
+---
+
+Add subscribe method to transition manager to allow subscribing and un-subscribing for React 18 strict mode compliance.
diff --git a/packages/remix-react/__tests__/transition-test.tsx b/packages/remix-react/__tests__/transition-test.tsx
index c4a37e78b3a..a0b87ed0e3c 100644
--- a/packages/remix-react/__tests__/transition-test.tsx
+++ b/packages/remix-react/__tests__/transition-test.tsx
@@ -28,7 +28,6 @@ describe("init", () => {
       actionData: { root: "ACTION DATA" },
       error: new Error("lol"),
       errorBoundaryId: "root",
-      onChange: () => {},
       onRedirect: () => {},
     });
     expect(tm.getState()).toMatchInlineSnapshot(`
@@ -1956,7 +1955,6 @@ function createTestTransitionManager(
     loaderData: { root: "ROOT" },
     location,
     routes: [],
-    onChange() {},
     onRedirect() {},
     ...init,
   });
@@ -2090,11 +2088,11 @@ let setup = ({ url } = { url: "/" }) => {
   ];
 
   let tm = createTestTransitionManager(url, {
-    onChange: handleChange,
     onRedirect: handleRedirect,
     loaderData: { root: "ROOT" },
     routes,
   });
+  tm.subscribe(handleChange);
 
   let navigate_ = (
     location: Location | string,
diff --git a/packages/remix-react/components.tsx b/packages/remix-react/components.tsx
index 3a6bef315da..4627a44e030 100644
--- a/packages/remix-react/components.tsx
+++ b/packages/remix-react/components.tsx
@@ -49,7 +49,12 @@ import type { RouteMatch as BaseRouteMatch } from "./routeMatching";
 import { matchClientRoutes } from "./routeMatching";
 import type { RouteModules, HtmlMetaDescriptor } from "./routeModules";
 import { createTransitionManager } from "./transition";
-import type { Transition, Fetcher, Submission } from "./transition";
+import type {
+  Transition,
+  TransitionManagerState,
+  Fetcher,
+  Submission,
+} from "./transition";
 
 ////////////////////////////////////////////////////////////////////////////////
 // RemixEntry
@@ -117,20 +122,25 @@ export function RemixEntry({
       catch: entryComponentDidCatchEmulator.catch,
       catchBoundaryId: entryComponentDidCatchEmulator.catchBoundaryRouteId,
       onRedirect: _navigator.replace,
-      onChange: (state) => {
-        setClientState({
-          catch: state.catch,
-          error: state.error,
-          catchBoundaryRouteId: state.catchBoundaryId,
-          loaderBoundaryRouteId: state.errorBoundaryId,
-          renderBoundaryRouteId: null,
-          trackBoundaries: false,
-          trackCatchBoundaries: false,
-        });
-      },
     });
   });
 
+  React.useEffect(() => {
+    let subscriber = (state: TransitionManagerState) => {
+      setClientState({
+        catch: state.catch,
+        error: state.error,
+        catchBoundaryRouteId: state.catchBoundaryId,
+        loaderBoundaryRouteId: state.errorBoundaryId,
+        renderBoundaryRouteId: null,
+        trackBoundaries: false,
+        trackCatchBoundaries: false,
+      });
+    };
+
+    return transitionManager.subscribe(subscriber);
+  }, [transitionManager]);
+
   // Ensures pushes interrupting pending navigations use replace
   // TODO: Move this to React Router
   let navigator: Navigator = React.useMemo(() => {
diff --git a/packages/remix-react/transition.ts b/packages/remix-react/transition.ts
index 346fd5d7637..0249db94826 100644
--- a/packages/remix-react/transition.ts
+++ b/packages/remix-react/transition.ts
@@ -97,10 +97,13 @@ export interface TransitionManagerInit {
   error?: Error;
   catchBoundaryId?: null | string;
   errorBoundaryId?: null | string;
-  onChange: (state: TransitionManagerState) => void;
   onRedirect: (to: string, state?: any) => void;
 }
 
+export type TransitionManagerSubscriber = (
+  state: TransitionManagerState
+) => void;
+
 export interface Submission {
   action: string;
   method: string;
@@ -422,6 +425,7 @@ export function createTransitionManager(init: TransitionManagerInit) {
   let navigationLoadId = -1;
   let fetchReloadIds = new Map<string, number>();
   let fetchRedirectIds = new Set<string>();
+  let subscribers = new Set<TransitionManagerSubscriber>();
 
   let matches = matchClientRoutes(routes, init.location);
 
@@ -462,7 +466,10 @@ export function createTransitionManager(init: TransitionManagerInit) {
     }
 
     state = Object.assign({}, state, updates);
-    init.onChange(state);
+
+    for (let subscriber of subscribers.values()) {
+      subscriber(state);
+    }
   }
 
   function getState(): TransitionManagerState {
@@ -1382,7 +1389,15 @@ export function createTransitionManager(init: TransitionManagerInit) {
     markFetchersDone(doneKeys);
   }
 
+  function subscribe(subscriber: TransitionManagerSubscriber) {
+    subscribers.add(subscriber);
+    return () => {
+      subscribers.delete(subscriber);
+    };
+  }
+
   return {
+    subscribe,
     send,
     getState,
     getFetcher,