refactor: bump minimum TypeScript version to 5.4. (#1773)

Author: igalklebanov

.github/workflows/test.yml

@@ -235,7 +235,6 @@ jobs:
       fail-fast: false
       matrix:
         typescript-version: [
-            ~5.3.0, # 20.11.2023 https://devblogs.microsoft.com/typescript/announcing-typescript-5-3/
             ~5.4.0, # 6.3.2024 https://devblogs.microsoft.com/typescript/announcing-typescript-5-4/
             ~5.8.0, # 28.2.2025 https://devblogs.microsoft.com/typescript/announcing-typescript-5-5/ https://devblogs.microsoft.com/typescript/announcing-typescript-5-6/ https://devblogs.microsoft.com/typescript/announcing-typescript-5-7/ https://devblogs.microsoft.com/typescript/announcing-typescript-5-8/
             ~5.9.0, # 1.8.2025 https://devblogs.microsoft.com/typescript/announcing-typescript-5-9/
@@ -268,15 +267,12 @@ jobs:
         run: |
           TS_VERSION="${{ matrix.typescript-version }}"
           echo "TS_VERSION=$TS_VERSION" >> $GITHUB_ENV
-          TSD_VERSION=$(echo '{"~5.3.0":"0.30.7", "~5.4.0":"0.31.2", "~5.8.0":"0.32.0", "~5.9.0":"0.33.0"}' | jq -r --arg key "$TS_VERSION" '.[$key]')
+          TSD_VERSION=$(echo '{"~5.4.0":"0.31.2", "~5.8.0":"0.32.0", "~5.9.0":"0.33.0"}' | jq -r --arg key "$TS_VERSION" '.[$key]')
           echo "TSD_VERSION=$TSD_VERSION" >> $GITHUB_ENV
 
       - name: Install Typescript (${{ env.TS_VERSION }}) and TSD (${{ env.TSD_VERSION }})
         run: pnpm i -D typescript@${{ env.TS_VERSION }} tsd@${{ env.TSD_VERSION }}
 
-      - name: Exclude non-backward compatible tests
-        run: pnpm script:exclude-test-files-for-backwards-compat
-
       - name: Run tests with older TypeScript version
         run: pnpm test:typings && pnpm test:node:build
 

outdated-typescript.d.ts

@@ -1,5 +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'The installed TypeScript version is outdated and cannot guarantee type-safety with Kysely.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 5.3 or newer.'>
-declare const RawBuilder: KyselyTypeError<'The installed TypeScript version is outdated and cannot guarantee type-safety with Kysely. Please upgrade to version 5.3 or newer.'>
-declare const sql: KyselyTypeError<'The installed TypeScript version is outdated and cannot guarantee type-safety with Kysely. Please upgrade to version 5.3 or newer.'>
+declare const Kysely: KyselyTypeError<'The installed TypeScript version is outdated and cannot guarantee type-safety with Kysely. Please upgrade to version 5.4 or newer.'>
+declare const RawBuilder: KyselyTypeError<'The installed TypeScript version is outdated and cannot guarantee type-safety with Kysely. Please upgrade to version 5.4 or newer.'>
+declare const sql: KyselyTypeError<'The installed TypeScript version is outdated and cannot guarantee type-safety with Kysely. Please upgrade to version 5.4 or newer.'>

package.json

@@ -31,7 +31,7 @@
   "main": "dist/cjs/index.js",
   "module": "dist/esm/index.js",
   "typesVersions": {
-    "<5.3": {
+    "<5.4": {
       "*": [
         "outdated-typescript.d.ts"
       ]
@@ -46,7 +46,7 @@
   ],
   "exports": {
     ".": {
-      "types@<5.3": "./outdated-typescript.d.ts",
+      "types@<5.4": "./outdated-typescript.d.ts",
       "import": "./dist/esm/index.js",
       "require": "./dist/cjs/index.js",
       "default": "./dist/cjs/index.js"
@@ -124,11 +124,11 @@
     "@types/better-sqlite3": "7.6.13",
     "@types/chai": "5.2.3",
     "@types/chai-as-promised": "8.0.2",
-    "@types/prototype-pollution-vulnerable-lodash.merge-dont-upgrade": "npm:@types/lodash.merge@4.6.1",
     "@types/mocha": "10.0.10",
     "@types/node": "25.5.0",
     "@types/pg": "8.20.0",
     "@types/pg-cursor": "2.7.2",
+    "@types/prototype-pollution-vulnerable-lodash.merge-dont-upgrade": "npm:@types/lodash.merge@4.6.1",
     "@types/semver": "7.7.1",
     "@types/sinon": "21.0.0",
     "better-sqlite3": "12.8.0",
@@ -140,12 +140,12 @@
     "mocha": "11.7.5",
     "mysql2": "3.20.0",
     "pathe": "2.0.3",
-    "prototype-pollution-vulnerable-lodash.merge-dont-upgrade": "npm:lodash.merge@4.6.1",
     "pg": "8.20.0",
     "pg-cursor": "2.19.0",
     "pkg-types": "2.3.0",
     "playwright": "1.58.2",
     "prettier": "3.8.1",
+    "prototype-pollution-vulnerable-lodash.merge-dont-upgrade": "npm:lodash.merge@4.6.1",
     "semver": "7.7.4",
     "sinon": "21.0.3",
     "std-env": "4.0.0",

pnpm-lock.yaml

@@ -1,6 +1,5 @@
 - [TypeScript](https://www.typescriptlang.org/)
-  - Minimum supported version [5.3](https://devblogs.microsoft.com/typescript/announcing-typescript-5.3).
-  - For even more type-safety and accurate inference, use version [5.4](https://devblogs.microsoft.com/typescript/announcing-typescript-5-4/#notable-behavioral-changes) or later.
+  - Minimum supported version [5.4](https://devblogs.microsoft.com/typescript/announcing-typescript-5.4).
   - For improved compilation performance, use version [5.9](https://devblogs.microsoft.com/typescript/announcing-typescript-5-9/#cache-instantiations-on-mappers) or later.
   - You must enable `strict` mode in your `tsconfig.json` file's `compilerOptions`:
 

scripts/exclude-test-files-for-backwards-compat.mts

@@ -2,7 +2,7 @@ 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 5.3 or newer.'>,
+  _: KyselyTypeError<'The installed TypeScript version is outdated and cannot guarantee type-safety with Kysely. Please upgrade to version 5.4 or newer.'>,
 ): void {}
 
 expectOutdatedTSError(Kysely)

site/docs/getting-started/_prerequisites.mdx

@@ -14,6 +14,6 @@
     "kysely": "file:../../"
   },
   "devDependencies": {
-    "typescript": "5.2.x"
+    "typescript": "5.3.x"
   }
 }