From 582ab138e10cae4551e30c65c4471fececd4ebe0 Mon Sep 17 00:00:00 2001
From: Natalie Rose <natalie@omg.lol>
Date: Fri, 18 Sep 2026 11:20:21 +1000
Subject: [PATCH] Fix hmr thing that broke the jest tests

---
 app/__mocks__/hmr.ts  |  7 +++++++
 app/hmr.ts            | 13 +++++++++++++
 app/lacuna.ts         | 14 ++++++--------
 app/stores/session.ts | 10 ++++------
 jest.config.js        |  4 ++++
 5 files changed, 34 insertions(+), 14 deletions(-)
 create mode 100644 app/__mocks__/hmr.ts
 create mode 100644 app/hmr.ts

diff --git a/app/__mocks__/hmr.ts b/app/__mocks__/hmr.ts
new file mode 100644
index 00000000..28ca1e4a
--- /dev/null
+++ b/app/__mocks__/hmr.ts
@@ -0,0 +1,7 @@
+// import.meta.hot doesn't exist outside Vite, so under Jest this is just a no-op stand-in
+// for app/hmr.ts.
+export function getHmrPreserved<T>(_key: string): T | undefined {
+  return undefined;
+}
+
+export function preserveOnHmr<T>(_key: string, _value: T): void {}
diff --git a/app/hmr.ts b/app/hmr.ts
new file mode 100644
index 00000000..9caea519
--- /dev/null
+++ b/app/hmr.ts
@@ -0,0 +1,13 @@
+// Isolated so the only `import.meta.hot` references in the app live in one file: Jest
+// forces ts-jest to compile to CommonJS, and TypeScript refuses `import.meta` syntax under
+// that module target (TS1343). jest.config.js maps this module to a no-op mock instead.
+export function getHmrPreserved<T>(key: string): T | undefined {
+  return import.meta.hot?.data[key];
+}
+
+export function preserveOnHmr<T>(key: string, value: T): void {
+  if (import.meta.hot) {
+    import.meta.hot.data[key] = value;
+    import.meta.hot.accept();
+  }
+}
diff --git a/app/lacuna.ts b/app/lacuna.ts
index 0c450651..639e777b 100644
--- a/app/lacuna.ts
+++ b/app/lacuna.ts
@@ -2,18 +2,19 @@ import { CAPTCHA_ERROR_CODE, Lacuna, SESSION_EXPIRED_ERROR_CODE } from '@tlecomm
 import * as vex from 'app/vex';
 import WindowsStore from 'app/stores/windows';
 import * as util from 'app/util';
+import { getHmrPreserved, preserveOnHmr } from 'app/hmr';
 import environment from './environment';
 import { splitStatus } from './server';
 import game from 'app/game';
 
 // Vite HMR can re-execute this module (e.g. when an update propagates up from an edited
-// component) without a full page reload. Reusing the instance via import.meta.hot.data keeps
+// component) without a full page reload. Reusing the instance preserved via app/hmr.ts keeps
 // the in-memory session id intact instead of resetting it, and guarding the setup below stops
 // onResponse from accumulating a duplicate handler on every such reload.
-const lacuna: Lacuna =
-  import.meta.hot?.data.lacuna ?? new Lacuna({ serverUrl: environment.getServerUrl() });
+const preservedLacuna = getHmrPreserved<Lacuna>('lacuna');
+const lacuna: Lacuna = preservedLacuna ?? new Lacuna({ serverUrl: environment.getServerUrl() });
 
-if (!import.meta.hot?.data.lacuna) {
+if (!preservedLacuna) {
   lacuna.log.setLogLevel('info');
 
   lacuna.onResponse(({ request, response, retry }) => {
@@ -63,9 +64,6 @@ if (!import.meta.hot?.data.lacuna) {
   });
 }
 
-if (import.meta.hot) {
-  import.meta.hot.data.lacuna = lacuna;
-  import.meta.hot.accept();
-}
+preserveOnHmr('lacuna', lacuna);
 
 export default lacuna;
diff --git a/app/stores/session.ts b/app/stores/session.ts
index feeb6eec..b4f0c954 100644
--- a/app/stores/session.ts
+++ b/app/stores/session.ts
@@ -1,4 +1,5 @@
 import { makeAutoObservable } from 'mobx';
+import { getHmrPreserved, preserveOnHmr } from 'app/hmr';
 
 class SessionStore {
   session = '';
@@ -13,13 +14,10 @@ class SessionStore {
 }
 
 // Vite HMR can re-execute this module (e.g. when an update propagates up from an edited
-// component) without a full page reload. Reusing the instance via import.meta.hot.data keeps
+// component) without a full page reload. Reusing the instance preserved via app/hmr.ts keeps
 // the in-memory session id intact instead of resetting to '' on every such reload.
-const store: SessionStore = import.meta.hot?.data.sessionStore ?? new SessionStore();
+const store: SessionStore = getHmrPreserved<SessionStore>('sessionStore') ?? new SessionStore();
 
-if (import.meta.hot) {
-  import.meta.hot.data.sessionStore = store;
-  import.meta.hot.accept();
-}
+preserveOnHmr('sessionStore', store);
 
 export default store;
diff --git a/jest.config.js b/jest.config.js
index a3cb54e5..0d6082a3 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -31,6 +31,10 @@ const config = {
     // react-markdown is ESM-only and cannot be required by Jest's CommonJS runtime
     '^react-markdown$': '<rootDir>/app/__mocks__/reactMarkdown.tsx',
 
+    // app/hmr.ts uses import.meta.hot, which TypeScript refuses to compile to the CommonJS
+    // module ts-jest forces for Jest (TS1343); swap in the no-op mock instead
+    '^app/hmr$': '<rootDir>/app/__mocks__/hmr.ts',
+
     // app/ absolute module alias
     'app/(.*)': '<rootDir>/app/$1',
   },
-- 
2.51.2