chore: make it build with strict null checks set to true (#9554)

As part of preparation for ESM and node/TSC updates, this PR will make
Unleash build with strictNullChecks set to true, since that's what's in
our tsconfig file. Hence, this PR also removes the `--strictNullChecks
false` flag in our compile tasks in package.json.

TL;DR - Clean up your code rather than turning off compiler security
features :)

Author: chriswk

package.json

@@ -35,21 +35,21 @@
   "scripts": {
     "start": "TZ=UTC node ./dist/server.js",
     "copy-templates": "copyfiles -u 1 src/mailtemplates/**/* dist/",
-    "build:backend": "tsc --pretty --strictNullChecks false",
+    "build:backend": "tsc --pretty",
     "build:frontend": "yarn --cwd ./frontend run build",
     "build:frontend:if-needed": "./scripts/build-frontend-if-needed.sh",
     "build": "yarn run clean && concurrently \"yarn:copy-templates\" \"yarn:build:frontend\" \"yarn:build:backend\"",
-    "dev:backend": "TZ=UTC NODE_ENV=development tsc-watch --strictNullChecks false --onSuccess \"node dist/server-dev.js\"",
+    "dev:backend": "TZ=UTC NODE_ENV=development tsc-watch --onSuccess \"node dist/server-dev.js\"",
     "dev:frontend": "wait-on tcp:4242 && yarn --cwd ./frontend run dev",
     "dev:frontend:cloud": "UNLEASH_BASE_PATH=/demo/ yarn run dev:frontend",
     "dev": "concurrently \"yarn:dev:backend\" \"yarn:dev:frontend\"",
     "prepare:backend": "concurrently \"yarn:copy-templates\" \"yarn:build:backend\"",
-    "start:dev": "yarn run clean && TZ=UTC NODE_ENV=development tsc-watch --strictNullChecks false --onSuccess \"node dist/server-dev.js\"",
+    "start:dev": "yarn run clean && TZ=UTC NODE_ENV=development tsc-watch --onSuccess \"node dist/server-dev.js\"",
     "db-migrate": "db-migrate --migrations-dir ./src/migrations",
     "lint": "biome check .",
     "lint:fix": "biome check . --write",
     "local:package": "del-cli --force build && mkdir build && cp -r dist docs CHANGELOG.md LICENSE README.md package.json build",
-    "build:watch": "yarn run clean && tsc -w --strictNullChecks false",
+    "build:watch": "tsc -w",
     "prepare": "husky && yarn --cwd ./frontend install && if [ ! -d ./dist ]; then yarn build; fi",
     "test": "NODE_ENV=test PORT=4243 node --trace-warnings node_modules/.bin/jest",
     "test:unit": "NODE_ENV=test PORT=4243 jest --testPathIgnorePatterns=src/test/e2e --testPathIgnorePatterns=dist",
@@ -60,7 +60,7 @@
     "test:coverage": "NODE_ENV=test PORT=4243 jest --coverage --testLocationInResults --outputFile=\"coverage/report.json\" --forceExit",
     "test:coverage:jest": "NODE_ENV=test PORT=4243 jest --silent --ci --json --coverage --testLocationInResults --outputFile=\"report.json\" --forceExit",
     "test:updateSnapshot": "NODE_ENV=test PORT=4243 jest --updateSnapshot",
-    "seed:setup": "ts-node --compilerOptions '{\"strictNullChecks\": false}' src/test/e2e/seed/segment.seed.ts",
+    "seed:setup": "ts-node src/test/e2e/seed/segment.seed.ts",
     "seed:serve": "UNLEASH_DATABASE_NAME=unleash_test UNLEASH_DATABASE_SCHEMA=seed yarn run start:dev",
     "clean": "del-cli --force dist",
     "heroku-postbuild": "cd frontend && yarn && yarn build",
@@ -220,7 +220,7 @@
     "supertest": "7.0.0",
     "ts-node": "10.9.2",
     "tsc-watch": "6.2.1",
-    "typescript": "5.4.5",
+    "typescript": "5.8.2",
     "wait-on": "^7.2.0"
   },
   "resolutions": {

src/lib/addons/datadog.ts

@@ -32,7 +32,7 @@ interface DDRequestBody {
 export default class DatadogAddon extends Addon {
     private msgFormatter: FeatureEventFormatter;
 
-    flagResolver: IFlagResolver;
+    declare flagResolver: IFlagResolver;
 
     constructor(config: IAddonConfig) {
         super(definition, config);

src/lib/addons/new-relic.ts

@@ -39,7 +39,7 @@ interface INewRelicRequestBody {
 export default class NewRelicAddon extends Addon {
     private msgFormatter: FeatureEventFormatter;
 
-    flagResolver: IFlagResolver;
+    declare flagResolver: IFlagResolver;
 
     constructor(config: IAddonConfig) {
         super(definition, config);

src/lib/addons/slack-app.ts

@@ -34,7 +34,7 @@ interface ISlackAppAddonParameters {
 export default class SlackAppAddon extends Addon {
     private msgFormatter: FeatureEventFormatter;
 
-    flagResolver: IFlagResolver;
+    declare flagResolver: IFlagResolver;
 
     private accessToken?: string;
 

src/lib/addons/slack.ts

@@ -25,7 +25,7 @@ interface ISlackAddonParameters {
 export default class SlackAddon extends Addon {
     private msgFormatter: FeatureEventFormatter;
 
-    flagResolver: IFlagResolver;
+    declare flagResolver: IFlagResolver;
 
     constructor(args: IAddonConfig) {
         super(slackDefinition, args);

src/lib/addons/teams.ts

@@ -38,7 +38,7 @@ interface ITeamsParameters {
 export default class TeamsAddon extends Addon {
     private msgFormatter: FeatureEventFormatter;
 
-    flagResolver: IFlagResolver;
+    declare flagResolver: IFlagResolver;
 
     constructor(args: IAddonConfig) {
         if (args.flagResolver.isEnabled('teamsIntegrationChangeRequests')) {

src/lib/addons/webhook.ts

@@ -25,7 +25,7 @@ interface IParameters {
 export default class Webhook extends Addon {
     private msgFormatter: FeatureEventFormatter;
 
-    flagResolver: IFlagResolver;
+    declare flagResolver: IFlagResolver;
 
     constructor(args: IAddonConfig) {
         super(definition, args);

src/lib/app.test.ts

@@ -18,10 +18,10 @@ jest.mock(
         },
 );
 
-const getApp = require('./app').default;
-
+import getApp from './app';
 test('should not throw when valid config', async () => {
     const config = createTestConfig();
+    // @ts-expect-error - We're passing in empty stores and services
     const app = await getApp(config, {}, {});
     expect(typeof app.listen).toBe('function');
 });
@@ -33,6 +33,7 @@ test('should call preHook', async () => {
             called++;
         },
     });
+    // @ts-expect-error - We're passing in empty stores and services
     await getApp(config, {}, {});
     expect(called).toBe(1);
 });
@@ -44,6 +45,7 @@ test('should call preRouterHook', async () => {
             called++;
         },
     });
+    // @ts-expect-error - We're passing in empty stores and services
     await getApp(config, {}, {});
     expect(called).toBe(1);
 });
@@ -82,6 +84,7 @@ describe('compression middleware', () => {
                     disableCompression: disableCompression as any,
                 },
             });
+            // @ts-expect-error - We're passing in empty stores and services
             await getApp(config, {}, {});
             expect(compression).toBeCalledTimes(+expectCompressionEnabled);
         },

src/lib/app.ts

@@ -195,6 +195,7 @@ export default async function getApp(
     }
 
     // Setup API routes
+    // @ts-expect-error - our db is possibly undefined and our indexrouter doesn't currently handle that
     app.use(`${baseUriPath}/`, new IndexRouter(config, services, db).router);
 
     if (process.env.NODE_ENV !== 'production') {

src/lib/create-config.ts

@@ -335,17 +335,22 @@ const parseEnvVarInitialAdminUser = (): UsernameAdminUser | undefined => {
     return username && password ? { username, password } : undefined;
 };
 
-const defaultAuthentication: IAuthOption = {
-    demoAllowAdminLogin: parseEnvVarBoolean(
-        process.env.AUTH_DEMO_ALLOW_ADMIN_LOGIN,
-        false,
-    ),
-    enableApiToken: parseEnvVarBoolean(process.env.AUTH_ENABLE_API_TOKEN, true),
-    type: authTypeFromString(process.env.AUTH_TYPE),
-    customAuthHandler: defaultCustomAuthDenyAll,
-    createAdminUser: true,
-    initialAdminUser: parseEnvVarInitialAdminUser(),
-    initApiTokens: [],
+const buildDefaultAuthOption = () => {
+    return {
+        demoAllowAdminLogin: parseEnvVarBoolean(
+            process.env.AUTH_DEMO_ALLOW_ADMIN_LOGIN,
+            false,
+        ),
+        enableApiToken: parseEnvVarBoolean(
+            process.env.AUTH_ENABLE_API_TOKEN,
+            true,
+        ),
+        type: authTypeFromString(process.env.AUTH_TYPE),
+        customAuthHandler: defaultCustomAuthDenyAll,
+        createAdminUser: true,
+        initialAdminUser: parseEnvVarInitialAdminUser(),
+        initApiTokens: [],
+    };
 };
 
 const defaultImport: WithOptional<IImportOption, 'file'> = {
@@ -563,7 +568,7 @@ export function createConfig(options: IUnleashOptions): IUnleashConfig {
     const initApiTokens = loadInitApiTokens();
 
     const authentication: IAuthOption = mergeAll([
-        defaultAuthentication,
+        buildDefaultAuthOption(),
         (options.authentication
             ? removeUndefinedKeys(options.authentication)
             : options.authentication) || {},