Rewrite TakeTwo, SkipTwo and Mutate to make them work for older ts versions too (#1348)

* create tsc v4.3.5 snapshot

* rewrite `TakeTwo` and `SkipTwo`
...to work with both pre 4.3.5 and post 4.3.5 subtyping rules.

The type `Test` in the following snippet resolves to `"yes"` for
<=4.3.5 but `"no"` for >4.3.5
```ts
type Test = [string, number?] extends [unknown] ? "yes" : "no"
```
(note 4.3.5 is bisected via typescript playground which skips
some versions so it might not be super accurate, but it's
accurate enough)

* fix lint

* fix pretest script to use tsc script instead of tsc bin

* revert tests

* add a workflow to test with old tsc

* fix typo

* oops, we need to run tsc

* test against build

* fix regex 🤦‍♂️

* oops, something was missing

* build in advance

* wip: more older versions

* wip: downgrade jest types

* minimum ts version 4.1.5

* minor fix

* make `Mutate` more complete
...wrt to the domain `StoreMutatorIdentifier[]` to help the type-checker

* fix lint

Co-authored-by: daishi <daishi@axlight.com>

.github/workflows/test-multiple-versions.yml

@@ -39,7 +39,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-node@v2
         with:
-          node-version: '12'
+          node-version: '14'
           cache: yarn
       - run: git fetch --depth=1 origin +refs/tags/*:refs/tags/*
       - run: yarn install --frozen-lockfile --check-files

.github/workflows/test-old-typescript.yml

@@ -0,0 +1,43 @@
+name: Test Old TypeScript
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    types: [opened, synchronize]
+
+jobs:
+  test_matrix:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        typescript:
+          - 4.8.4
+          - 4.7.4
+          - 4.6.4
+          - 4.5.5
+          - 4.4.4
+          - 4.3.5
+          - 4.2.3
+          - 4.1.5
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: '14'
+          cache: yarn
+      - run: git fetch --depth=1 origin +refs/tags/*:refs/tags/*
+      - run: yarn install --frozen-lockfile --check-files
+      - run: yarn build
+      - name: Patch for Old TS
+        run: |
+          sed -i~ "s/\/\/ @ts-expect-error.*\[LATEST-TS-ONLY\]//" tests/*.tsx
+          sed -i~ "s/\"exactOptionalPropertyTypes\": true,//" tsconfig.json
+          sed -i~ "s/\"zustand\": \[\"\.\/src\/index\.ts\"\],/\"zustand\": [\".\/dist\/index.d.ts\"],/" tsconfig.json
+          sed -i~ "s/\"zustand\/\*\": \[\"\.\/src\/\*\.ts\"\]/\"zustand\/*\": [\".\/dist\/*.d.ts\"]/" tsconfig.json
+          sed -i~ "s/\"include\": .*/\"include\": [\"src\/types.d.ts\", \"dist\/**\/*\", \"tests\/**\/*\"],/" tsconfig.json
+      - name: Test ${{ matrix.typescript }}
+        run: |
+          yarn add -D typescript@${{ matrix.typescript }}
+          yarn tsc --noEmit

src/middleware/devtools.ts

@@ -85,18 +85,19 @@ type Message = {
   state?: any
 }
 
+type Cast<T, U> = T extends U ? T : U
 type Write<T, U> = Omit<T, keyof U> & U
-type TakeTwo<T> = T extends []
+type TakeTwo<T> = T extends { length: 0 }
   ? [undefined, undefined]
-  : T extends [unknown]
-  ? [...a0: T, a1: undefined]
-  : T extends [unknown?]
-  ? [...a0: T, a1: undefined]
-  : T extends [unknown, unknown]
+  : T extends { length: 1 }
+  ? [...a0: Cast<T, unknown[]>, a1: undefined]
+  : T extends { length: 0 | 1 }
+  ? [...a0: Cast<T, unknown[]>, a1: undefined]
+  : T extends { length: 2 }
   ? T
-  : T extends [unknown, unknown?]
+  : T extends { length: 1 | 2 }
   ? T
-  : T extends [unknown?, unknown?]
+  : T extends { length: 0 | 1 | 2 }
   ? T
   : T extends [infer A0, infer A1, ...unknown[]]
   ? [A0, A1]

src/middleware/immer.ts

@@ -18,11 +18,11 @@ declare module '../vanilla' {
 }
 
 type Write<T, U> = Omit<T, keyof U> & U
-type SkipTwo<T> = T extends []
+type SkipTwo<T> = T extends { length: 0 }
   ? []
-  : T extends [unknown]
+  : T extends { length: 1 }
   ? []
-  : T extends [unknown?]
+  : T extends { length: 0 | 1 }
   ? []
   : T extends [unknown, unknown, ...infer A]
   ? A

src/vanilla.ts

@@ -14,7 +14,9 @@ export interface StoreApi<T> {
 
 type Get<T, K, F = never> = K extends keyof T ? T[K] : F
 
-export type Mutate<S, Ms> = Ms extends []
+export type Mutate<S, Ms> = number extends Ms['length' & keyof Ms]
+  ? S
+  : Ms extends []
   ? S
   : Ms extends [[infer Mi, infer Ma], ...infer Mrs]
   ? Mutate<StoreMutators<S, Ma>[Mi & StoreMutatorIdentifier], Mrs>

tests/types.test.tsx

@@ -106,9 +106,9 @@ it('should have correct (partial) types for setState', () => {
 
   const store = create<Count>((set) => ({
     count: 0,
-    // @ts-expect-error we shouldn't be able to set count to undefined
+    // @ts-expect-error we shouldn't be able to set count to undefined [LATEST-TS-ONLY]
     a: () => set(() => ({ count: undefined })),
-    // @ts-expect-error we shouldn't be able to set count to undefined
+    // @ts-expect-error we shouldn't be able to set count to undefined [LATEST-TS-ONLY]
     b: () => set({ count: undefined }),
     c: () => set({ count: 1 }),
   }))
@@ -124,9 +124,9 @@ it('should have correct (partial) types for setState', () => {
   store.setState({})
   store.setState((previous) => previous)
 
-  // @ts-expect-error type undefined is not assignable to type number
+  // @ts-expect-error type undefined is not assignable to type number [LATEST-TS-ONLY]
   store.setState({ count: undefined })
-  // @ts-expect-error type undefined is not assignable to type number
+  // @ts-expect-error type undefined is not assignable to type number [LATEST-TS-ONLY]
   store.setState((state) => ({ ...state, count: undefined }))
 })