chore: enforce min TS version (#1194)

.github/workflows/test.yml

@@ -205,11 +205,34 @@ jobs:
       - name: Run build with newer TypeScript
         run: npm run build
 
-      - name: Install older TypeScript
-        run: npm i -D typescript@${{ matrix.typescript-version }} tsd@${{ fromJson('{ "^4.6":"0.20.0", "^4.7":"0.22.0", "^4.8":"0.24.1", "^4.9":"0.27.0", "^5.0":"0.28.1", "^5.2":"0.29.0", "^5.3":"0.30.7", "^5.4":"0.31.2" }')[matrix.typescript-version] }}
+      - run: |
+          echo "TS_VERSION=${{ matrix.typescript-version }}" >> $GITHUB_ENV
+          echo "TSD_VERSION=${{ fromJson('{ "^4.6":"0.20.0", "^4.7":"0.22.0", "^4.8":"0.24.1", "^4.9":"0.27.0", "^5.0":"0.28.1", "^5.2":"0.29.0", "^5.3":"0.30.7", "^5.4":"0.31.2" }')[env.TS_VERSION] }} >> $GITHUB_ENV"
+
+      - name: Install Typescript (${{ env.TS_VERSION }}) and TSD (${{ env.TSD_VERSION }})
+        run: npm i -D typescript@${{ env.TS_VERSION }} tsd@${{ env.TSD_VERSION }}
 
       - name: Exclude non-backward compatible tests
         run: npx tsx ./scripts/exclude-test-files-for-backwards-compat.mts
 
-      - name: Run tests with older TypeScript
+      - name: Run tests with older TypeScript version
         run: npm run test:typings && npm run test:node:build
+
+  outdated-typescript-version:
+    name: Outdated TypeScript version (<4.6)
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Use Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 18.x
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Test outdated TypeScript version
+        run: npm run test:outdatedts && echo "Outdated TypeScript version users are required to upgrade!"

.npmignore

@@ -16,4 +16,4 @@ package-lock.json
 tsconfig-base.json
 tsconfig-cjs.json
 tsconfig.json
-
+CONTRIBUTING.md

outdated-typescript.d.ts

@@ -0,0 +1,5 @@
+import type { KyselyTypeError } from './dist/cjs/util/type-error'
+
+declare const Kysely: KyselyTypeError<'The installed TypeScript version is outdated and cannot guarantee type-safety with Kysely. Please upgrade to version 4.6 or newer.'>
+declare const RawBuilder: KyselyTypeError<'The installed TypeScript version is outdated and cannot guarantee type-safety with Kysely. Please upgrade to version 4.6 or newer.'>
+declare const sql: KyselyTypeError<'The installed TypeScript version is outdated and cannot guarantee type-safety with Kysely. Please upgrade to version 4.6 or newer.'>

package.json

@@ -7,10 +7,17 @@
     "url": "git://github.com/kysely-org/kysely.git"
   },
   "engines": {
-    "node": ">=14.0.0"
+    "node": ">=18.0.0"
   },
   "main": "dist/cjs/index.js",
   "module": "dist/esm/index.js",
+  "typesVersions": {
+    "<4.6": {
+      "*": [
+        "outdated-typescript.d.ts"
+      ]
+    }
+  },
   "exports": {
     ".": {
       "import": "./dist/esm/index.js",
@@ -53,6 +60,7 @@
     "test:esmimports": "node scripts/check-esm-imports.js",
     "test:esbuild": "esbuild --bundle --platform=node --external:pg-native dist/esm/index.js --outfile=/dev/null",
     "test:exports": "attw --pack . && node scripts/check-exports.js",
+    "test:outdatedts": "npm run build && cd test/outdated-ts && npm ci && npm test",
     "prettier": "prettier --write 'src/**/*.ts' 'test/**/*.ts'",
     "build": "npm run clean && (npm run build:esm & npm run build:cjs) && npm run script:module-fixup && npm run script:copy-interface-doc",
     "build:esm": "tsc -p tsconfig.json && npm run script:add-deno-type-references",

test/outdated-ts/outdated-ts.test.ts

@@ -0,0 +1,10 @@
+import { Kysely, RawBuilder, sql } from 'kysely'
+import { KyselyTypeError } from '../../src/util/type-error'
+
+function expectOutdatedTSError(
+  _: KyselyTypeError<'The installed TypeScript version is outdated and cannot guarantee type-safety with Kysely. Please upgrade to version 4.6 or newer.'>,
+): void {}
+
+expectOutdatedTSError(Kysely)
+expectOutdatedTSError(RawBuilder)
+expectOutdatedTSError(sql)