Revert "drop pre-TS-4.1 types and workarounds (#2249)"

This reverts commit 48689d4.

.github/workflows/tests.yml

@@ -96,7 +96,7 @@ jobs:
       fail-fast: false
       matrix:
         node: ['14.x']
-        ts: ['4.1', '4.2', '4.3', '4.4', '4.5', '4.6', '4.7.0-beta', 'next']
+        ts: ['4.1', '4.2', '4.3', '4.4', '4.5', '4.6.1-rc', 'next']
     steps:
       - name: Checkout repo
         uses: actions/checkout@v2
@@ -123,6 +123,10 @@ jobs:
 
       - run: sed -i -e /@remap-prod-remove-line/d ./tsconfig.base.json ./jest.config.js ./src/tests/*.* ./src/query/tests/*.*
 
+      - name: "@ts-ignore stuff that didn't exist pre-4.1 in the tests"
+        if: ${{ matrix.ts < 4.1 }}
+        run: sed -i -e 's/@pre41-ts-ignore/@ts-ignore/' -e  '/pre41-remove-start/,/pre41-remove-end/d' ./src/tests/*.* ./src/query/tests/*.ts*
+
       - name: Test types
         run: |
           yarn tsc --version

packages/toolkit/scripts/build.ts

@@ -326,6 +326,13 @@ async function main({ skipExtraction = false, local = false }: BuildArgs) {
     await buildUMD(outputPath, entryPoint.prefix, entryPoint.globalName)
   }
 
+  // We need one additional package.json file in dist to support
+  // versioned types for TS <4.1
+  fs.copyFileSync(
+    'src/query/react/versionedTypes/package.dist.json',
+    'dist/query/react/versionedTypes/package.json'
+  )
+
   if (!skipExtraction) {
     for (let entryPoint of entryPoints) {
       try {

packages/toolkit/src/query/react/module.ts

@@ -12,7 +12,7 @@ import { capitalize } from '../utils'
 import { safeAssign } from '../tsHelpers'
 import type { BaseQueryFn } from '@reduxjs/toolkit/dist/query/baseQueryTypes'
 
-import type { HooksWithUniqueNames } from './namedHooks'
+import type { HooksWithUniqueNames } from './versionedTypes'
 
 import {
   useDispatch as rrUseDispatch,

packages/toolkit/src/query/react/versionedTypes/index.ts

@@ -0,0 +1,8 @@
+// This file is a dummy. In actual dev, we re-export the hooks type
+// here. But, when published, the package.json in this folder will
+// point TS to either ts40Types.d.ts or ts41Types.d.ts, and bypass
+// index.d.ts completely.
+// Overall, this setup allows us to selectively override the one
+// file that has any difference between 4.1 and earlier, without
+// having to ship two completely duplicate copies of our typedefs.
+export { HooksWithUniqueNames } from './ts41Types'

packages/toolkit/src/query/react/versionedTypes/package.dist.json

@@ -0,0 +1,10 @@
+{
+  "typesVersions": {
+    ">=4.1": {
+      "index": ["./ts41Types.d.ts"]
+    },
+    "<4.1": {
+      "index": ["./ts40Types.d.ts"]
+    }
+  }
+}

packages/toolkit/src/query/react/versionedTypes/ts40Types.ts

@@ -0,0 +1,9 @@
+import type { EndpointDefinitions } from '@reduxjs/toolkit/dist/query/endpointDefinitions'
+
+// For TS 4.0 and earlier, disallow use of the per-endpoint
+// hooks defined at the root of each API object, because we
+// can't use the string literal types here.
+export declare type HooksWithUniqueNames<
+  Definitions extends EndpointDefinitions
+> = unknown
+export {}

packages/toolkit/src/query/react/namedHooks.ts → packages/toolkit/src/query/react/versionedTypes/ts41Types.ts

@@ -1,11 +1,13 @@
-import type { UseMutation, UseLazyQuery, UseQuery } from './buildHooks'
+import type { UseMutation, UseLazyQuery, UseQuery } from '../buildHooks'
 import type {
   DefinitionType,
   EndpointDefinitions,
   MutationDefinition,
   QueryDefinition,
 } from '@reduxjs/toolkit/dist/query/endpointDefinitions'
 
+// For TS 4.1 and later, we can use string literal types to define
+// the exact names of each endpoint's exported hooks
 export type HooksWithUniqueNames<Definitions extends EndpointDefinitions> =
   keyof Definitions extends infer Keys
     ? Keys extends string

packages/toolkit/src/query/tests/buildHooks.test.tsx

@@ -1828,10 +1828,14 @@ describe('hooks with createApi defaults set', () => {
 
     const storeRef = setupApiStore(api)
 
+    // @pre41-ts-ignore
     expectExactType(api.useGetPostsQuery)(api.endpoints.getPosts.useQuery)
+    // @pre41-ts-ignore
     expectExactType(api.useUpdatePostMutation)(
+      // @pre41-ts-ignore
       api.endpoints.updatePost.useMutation
     )
+    // @pre41-ts-ignore
     expectExactType(api.useAddPostMutation)(api.endpoints.addPost.useMutation)
 
     test('useQueryState serves a deeply memoized value and does not rerender unnecessarily', async () => {

packages/toolkit/src/query/tests/unionTypes.test.ts

@@ -141,6 +141,7 @@ describe.skip('TS only tests', () => {
       expectType<never>(result)
     }
   })
+  // pre41-remove-start
   test('useQuery TS4.1 union', () => {
     const result = api.useTestQuery()
 
@@ -206,6 +207,7 @@ describe.skip('TS only tests', () => {
       expectType<never>(result)
     }
   })
+  // pre41-remove-end
 
   test('useLazyQuery union', () => {
     const [_trigger, result] = api.endpoints.test.useLazyQuery()
@@ -273,6 +275,7 @@ describe.skip('TS only tests', () => {
     }
   })
 
+  // pre41-remove-start
   test('useLazyQuery TS4.1 union', () => {
     const [_trigger, result] = api.useLazyTestQuery()
 
@@ -338,6 +341,7 @@ describe.skip('TS only tests', () => {
       expectType<never>(result)
     }
   })
+  // pre41-remove-end
 
   test('queryHookResult (without selector) union', () => {
     const useQueryStateResult = api.endpoints.test.useQueryState()
@@ -497,6 +501,7 @@ describe.skip('TS only tests', () => {
     })(result)
   })
 
+  // pre41-remove-start
   test('useMutation TS4.1 union', () => {
     const [_trigger, result] = api.useMutationMutation()
 
@@ -547,4 +552,5 @@ describe.skip('TS only tests', () => {
       expectType<never>(result)
     }
   })
+  // pre41-remove-end
 })