✨ Extend tsconfig from @tsconfig/node26 and @tsconfig/strictest

- Replace hand-rolled strict flags with @tsconfig/strictest
- Pick up Node 26 module/lib/target from @tsconfig/node26
- Add exactOptionalPropertyTypes (the main strictness gain)
- Pin target to es2024 to remain conservative for the published build

package-lock.json

@@ -9,6 +9,8 @@
             "version": "0.0.0",
             "license": "MIT",
             "devDependencies": {
+                "@tsconfig/node26": "^26.0.1",
+                "@tsconfig/strictest": "^2.0.8",
                 "@types/node": "^26.4.1",
                 "c8": "^12.0.0",
                 "check-outdated": "^3.0.0",
@@ -1398,6 +1400,20 @@
                 "node": "^20.19.0 || >=22.12.0"
             }
         },
+        "node_modules/@tsconfig/node26": {
+            "version": "26.0.1",
+            "resolved": "https://registry.npmjs.org/@tsconfig/node26/-/node26-26.0.1.tgz",
+            "integrity": "sha512-NQT8JUFDKeAIWpR1dakeF534msQAsoSLr1WpKdRDt3sCvk2fsFK3EVKUBG5xKYVamiRO6yTfniiyvCaqOGgn/g==",
+            "dev": true,
+            "license": "MIT"
+        },
+        "node_modules/@tsconfig/strictest": {
+            "version": "2.0.8",
+            "resolved": "https://registry.npmjs.org/@tsconfig/strictest/-/strictest-2.0.8.tgz",
+            "integrity": "sha512-XnQ7vNz5HRN0r88GYf1J9JJjqtZPiHt2woGJOo2dYqyHGGcd6OLGqSlBB6p1j9mpzja6Oe5BoPqWmeDx6X9rLw==",
+            "dev": true,
+            "license": "MIT"
+        },
         "node_modules/@types/istanbul-lib-coverage": {
             "version": "2.0.6",
             "resolved": "https://registry.npmjs.org/@types/istanbul-lib-coverage/-/istanbul-lib-coverage-2.0.6.tgz",

package.json

@@ -50,6 +50,8 @@
         "use:git-commit-message": "cp commit-message-template .git/COMMIT_EDITMSG || true"
     },
     "devDependencies": {
+        "@tsconfig/node26": "^26.0.1",
+        "@tsconfig/strictest": "^2.0.8",
         "@types/node": "^26.4.1",
         "c8": "^12.0.0",
         "check-outdated": "^3.0.0",
@@ -80,5 +82,8 @@
     },
     "engines": {
         "node": ">=26"
+    },
+    "allowScripts": {
+        "lefthook@2.1.12": true
     }
 }

tsconfig.json

@@ -1,39 +1,21 @@
 {
+    "extends": [
+        "@tsconfig/node26/tsconfig.json",
+        "@tsconfig/strictest/tsconfig.json"
+    ],
     "compilerOptions": {
         "noEmit": true,
         "target": "es2024",
-        "module": "nodenext",
-        "moduleResolution": "nodenext",
-        "moduleDetection": "force",
         "lib": ["es2024"],
-        "skipLibCheck": true,
-        "strict": true,
-        "noImplicitAny": true,
-        "noImplicitThis": true,
-        "alwaysStrict": true,
-        "strictNullChecks": true,
-        "strictFunctionTypes": true,
-        "strictBindCallApply": true,
-        "strictPropertyInitialization": true,
-        "noImplicitReturns": true,
-        "noFallthroughCasesInSwitch": true,
-        "noUncheckedIndexedAccess": true,
-        "noImplicitOverride": true,
-        "forceConsistentCasingInFileNames": true,
-        "noUnusedLocals": true,
-        "noUnusedParameters": true,
-        "isolatedModules": true,
         "verbatimModuleSyntax": true,
         "allowImportingTsExtensions": true,
         "declaration": true,
         "declarationMap": true,
         "sourceMap": true,
         "outDir": "dist",
-        "esModuleInterop": true,
         "allowSyntheticDefaultImports": true,
         "resolveJsonModule": true,
-        "composite": false,
-        "types": ["node"]
+        "composite": false
     },
     "include": ["src"]
 }