Convert @emotion/react's source code to TypeScript (#3281)

* Convert `@emotion/react`'s source code to TypeScript

* add changeset

* limit `package.json['files']`

* fixed type issue

* try `esModuleInterop`

* add required cast

* use `resolveJsonModule` too

* fixed extra things

* fixed a silly mistake

* one extra thing

* fixed type error

* try building before running dtslint

* fixed import

* try to bump tested TS versions

* add extra ts-ignore

* make sure the ts-ignore is above the problematic line

* rewrite tests to stop relying on implementation detail

* fixed type error

* corrext tests

* fixed entrypoints types

.changeset/rotten-baboons-knock.md

@@ -0,0 +1,5 @@
+---
+'@emotion/react': minor
+---
+
+Source code has been migrated to TypeScript. From now on type declarations will be emitted based on that, instead of being hand-written.

.github/workflows/main.yml

@@ -88,5 +88,8 @@ jobs:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/ci-setup
 
+      - name: build
+        run: yarn build
+
       - name: dtslint
         run: yarn test:typescript

package.json

@@ -188,7 +188,7 @@
     "@testing-library/react": "13.0.0-alpha.5",
     "@types/jest": "^29.5.12",
     "@types/node": "^12.20.37",
-    "@types/react": "18.2.6",
+    "@types/react": "18.3.12",
     "@typescript-eslint/eslint-plugin": "^7.13.0",
     "@typescript-eslint/parser": "^7.13.0",
     "babel-check-duplicated-nodes": "^1.0.0",

packages/cache/types/index.d.ts

@@ -1 +1 @@
-export * from '../src'
+export * from '..'

packages/css/test/no-babel/index.test.js

@@ -7,7 +7,6 @@ import styled from '@emotion/styled'
 let consoleError = console.error
 
 afterEach(() => {
-  // $FlowFixMe
   console.error = consoleError
 })
 
@@ -146,7 +145,6 @@ describe('css', () => {
     })
 
     const spy = jest.fn()
-    // $FlowFixMe
     console.error = spy
 
     expect(() =>

packages/css/test/sheet.dom.test.js

@@ -3,7 +3,6 @@ import { sheet } from '@emotion/css'
 const consoleError = console.error
 
 afterEach(() => {
-  // $FlowFixMe
   console.error = consoleError
 })
 
@@ -38,7 +37,6 @@ describe('sheet', () => {
   test('throws', () => {
     sheet.speedy(true)
     const spy = jest.fn()
-    // $FlowFixMe
     console.error = spy
     sheet.insert('.asdfasdf4###112121211{')
     expect(spy.mock.calls.length).toBe(1)

packages/native/types/index.d.ts

@@ -1,5 +1,5 @@
 // Definitions by: Pat Sissons <https://github.com/patsissons>
-// TypeScript Version: 3.4
+// TypeScript Version: 4.1
 
 import * as RN from 'react-native'
 import { Theme } from '@emotion/react'

packages/native/types/tsconfig.json

@@ -5,6 +5,8 @@
     "jsx": "react",
     "lib": ["es6", "dom"],
     "module": "commonjs",
+    "esModuleInterop": true,
+    "resolveJsonModule": true,
     "noEmit": true,
     "strict": true,
     "target": "es5",

packages/primitives-core/src/styled.ts

@@ -51,7 +51,8 @@ export function createStyled(
 
       // do we really want to use the same infra as the web since it only really uses theming?
       let Styled = React.forwardRef<unknown, StyledProps>((props, ref) => {
-        const finalTag = (shouldUseAs && props.as) || component
+        const finalTag =
+          (shouldUseAs && (props.as as React.ElementType)) || component
 
         let mergedProps = props
         if (props.theme == null) {

packages/react/__tests__/element.js

@@ -1,14 +1,11 @@
-// @flow
 /** @jsx jsx */
 import { render } from '@testing-library/react'
 import { jsx, css, CacheProvider, ThemeProvider } from '@emotion/react'
 import createCache from '@emotion/cache'
 
-// $FlowFixMe
 console.error = jest.fn()
 
 beforeEach(() => {
-  // $FlowFixMe
   document.head.innerHTML = ''
   jest.clearAllMocks()
 })
@@ -18,7 +15,6 @@ describe('EmotionElement', () => {
     const theme = { color: 'blue' }
     const cache = createCache({ key: 'context' })
 
-    // $FlowFixMe
     const Comp = ({ flag }) => (
       <ThemeProvider theme={theme}>
         <CacheProvider value={cache}>

packages/react/__tests__/get-label-from-stack-trace.js

@@ -1,4 +1,3 @@
-// @flow
 import { getLabelFromStackTrace } from '../src/get-label-from-stack-trace'
 
 /**

packages/react/__tests__/global.js

@@ -9,7 +9,6 @@ import {
 } from '@emotion/react'
 import createCache from '@emotion/cache'
 
-// $FlowFixMe
 console.error = jest.fn()
 
 beforeEach(() => {

packages/react/__tests__/import-prod.js

@@ -23,7 +23,6 @@ expect.addSnapshotSerializer({
 const render = children =>
   new Promise(resolve => {
     const el = document.createElement('div')
-    // $FlowFixMe
     document.body.appendChild(el)
 
     if (ReactDOM.createRoot) {

packages/react/__tests__/theme-provider.dom.js

@@ -6,7 +6,6 @@ import * as React from 'react'
 import { jsx, ThemeProvider } from '@emotion/react'
 
 beforeEach(() => {
-  // $FlowFixMe
   document.head.innerHTML = ''
 })
 

packages/react/_isolated-hnrs/package.json

@@ -2,6 +2,7 @@
   "main": "dist/emotion-react-_isolated-hnrs.cjs.js",
   "module": "dist/emotion-react-_isolated-hnrs.esm.js",
   "umd:main": "dist/emotion-react-_isolated-hnrs.umd.min.js",
+  "types": "dist/emotion-react-_isolated-hnrs.cjs.d.ts",
   "sideEffects": false,
   "preconstruct": {
     "umdName": "emotionHoistNonReactStatics"

packages/react/jsx-dev-runtime/package.json

@@ -2,7 +2,7 @@
   "main": "dist/emotion-react-jsx-dev-runtime.cjs.js",
   "module": "dist/emotion-react-jsx-dev-runtime.esm.js",
   "umd:main": "dist/emotion-react-jsx-dev-runtime.umd.min.js",
-  "types": "../types/jsx-dev-runtime",
+  "types": "dist/emotion-react-jsx-dev-runtime.cjs.d.ts",
   "sideEffects": false,
   "preconstruct": {
     "umdName": "emotionReactJSXDevRuntime"

packages/react/jsx-runtime/package.json

@@ -2,7 +2,7 @@
   "main": "dist/emotion-react-jsx-runtime.cjs.js",
   "module": "dist/emotion-react-jsx-runtime.esm.js",
   "umd:main": "dist/emotion-react-jsx-runtime.umd.min.js",
-  "types": "../types/jsx-runtime",
+  "types": "dist/emotion-react-jsx-runtime.cjs.d.ts",
   "sideEffects": false,
   "preconstruct": {
     "umdName": "emotionReactJSXRuntime"

packages/react/package.json

@@ -3,6 +3,7 @@
   "version": "11.13.5",
   "main": "dist/emotion-react.cjs.js",
   "module": "dist/emotion-react.esm.js",
+  "types": "dist/emotion-react.cjs.d.ts",
   "exports": {
     ".": {
       "types": {
@@ -232,25 +233,24 @@
   },
   "imports": {
     "#is-development": {
-      "development": "./src/conditions/true.js",
-      "default": "./src/conditions/false.js"
+      "development": "./src/conditions/true.ts",
+      "default": "./src/conditions/false.ts"
     },
     "#is-browser": {
-      "edge-light": "./src/conditions/false.js",
-      "workerd": "./src/conditions/false.js",
-      "worker": "./src/conditions/false.js",
-      "browser": "./src/conditions/true.js",
-      "default": "./src/conditions/is-browser.js"
+      "edge-light": "./src/conditions/false.ts",
+      "workerd": "./src/conditions/false.ts",
+      "worker": "./src/conditions/false.ts",
+      "browser": "./src/conditions/true.ts",
+      "default": "./src/conditions/is-browser.ts"
     }
   },
-  "types": "types/index.d.ts",
   "files": [
     "src",
     "dist",
     "jsx-runtime",
     "jsx-dev-runtime",
     "_isolated-hnrs",
-    "types/*.d.ts",
+    "types/css-prop.d.ts",
     "macro.*"
   ],
   "sideEffects": false,
@@ -283,6 +283,7 @@
     "@emotion/css-prettifier": "1.1.4",
     "@emotion/server": "11.11.0",
     "@emotion/styled": "11.13.5",
+    "@types/hoist-non-react-statics": "^3.3.5",
     "html-tag-names": "^1.1.2",
     "react": "16.14.0",
     "svg-tag-names": "^1.1.1",
@@ -295,10 +296,10 @@
   "umd:main": "dist/emotion-react.umd.min.js",
   "preconstruct": {
     "entrypoints": [
-      "./index.js",
-      "./jsx-runtime.js",
-      "./jsx-dev-runtime.js",
-      "./_isolated-hnrs.js"
+      "./index.ts",
+      "./jsx-runtime.ts",
+      "./jsx-dev-runtime.ts",
+      "./_isolated-hnrs.ts"
     ],
     "umdName": "emotionReact",
     "exports": {

packages/react/src/_isolated-hnrs.js → packages/react/src/_isolated-hnrs.ts

@@ -6,5 +6,10 @@ import hoistNonReactStatics from 'hoist-non-react-statics'
 // have to wrap it in a proxy function because Rollup is too damn smart
 // and if this module doesn't actually contain any logic of its own
 // then Rollup just use 'hoist-non-react-statics' directly in other chunks
-export default (targetComponent, sourceComponent) =>
-  hoistNonReactStatics(targetComponent, sourceComponent)
+export default <
+  T extends React.ComponentType<any>,
+  S extends React.ComponentType<any>
+>(
+  targetComponent: T,
+  sourceComponent: S
+) => hoistNonReactStatics(targetComponent, sourceComponent)

packages/react/src/class-names.js → packages/react/src/class-names.tsx

@@ -1,27 +1,29 @@
 import * as React from 'react'
 import {
+  EmotionCache,
   getRegisteredStyles,
   insertStyles,
-  registerStyles
+  registerStyles,
+  SerializedStyles
 } from '@emotion/utils'
-import { serializeStyles } from '@emotion/serialize'
+import { CSSInterpolation, serializeStyles } from '@emotion/serialize'
 import isDevelopment from '#is-development'
 import { withEmotionCache } from './context'
-import { ThemeContext } from './theming'
+import { Theme, ThemeContext } from './theming'
 import { useInsertionEffectAlwaysWithSyncFallback } from '@emotion/use-insertion-effect-with-fallbacks'
 import isBrowser from '#is-browser'
 
-/*
-type ClassNameArg =
+export interface ArrayClassNamesArg extends Array<ClassNamesArg> {}
+
+export type ClassNamesArg =
+  | undefined
+  | null
   | string
   | boolean
-  | { [key: string]: boolean }
-  | Array<ClassNameArg>
-  | null
-  | void
-*/
+  | { [className: string]: boolean | null | undefined }
+  | ArrayClassNamesArg
 
-let classnames = (args /*: Array<ClassNameArg> */) /*: string */ => {
+let classnames = (args: ArrayClassNamesArg): string => {
   let len = args.length
   let i = 0
   let cls = ''
@@ -69,11 +71,11 @@ let classnames = (args /*: Array<ClassNameArg> */) /*: string */ => {
   return cls
 }
 function merge(
-  registered /*: Object */,
-  css /*: (...args: Array<any>) => string */,
-  className /*: string */
+  registered: EmotionCache['registered'],
+  css: ClassNamesContent['css'],
+  className: string
 ) {
-  const registeredStyles = []
+  const registeredStyles: string[] = []
 
   const rawClassName = getRegisteredStyles(
     registered,
@@ -87,7 +89,13 @@ function merge(
   return rawClassName + css(registeredStyles)
 }
 
-const Insertion = ({ cache, serializedArr }) => {
+const Insertion = ({
+  cache,
+  serializedArr
+}: {
+  cache: EmotionCache
+  serializedArr: SerializedStyles[]
+}) => {
   let rules = useInsertionEffectAlwaysWithSyncFallback(() => {
     let rules = ''
     for (let i = 0; i < serializedArr.length; i++) {
@@ -101,14 +109,14 @@ const Insertion = ({ cache, serializedArr }) => {
     }
   })
 
-  if (!isBrowser && rules.length !== 0) {
+  if (!isBrowser && rules!.length !== 0) {
     return (
       <style
         {...{
           [`data-emotion`]: `${cache.key} ${serializedArr
             .map(serialized => serialized.name)
             .join(' ')}`,
-          dangerouslySetInnerHTML: { __html: rules },
+          dangerouslySetInnerHTML: { __html: rules! },
           nonce: cache.sheet.nonce
         }}
       />
@@ -117,21 +125,23 @@ const Insertion = ({ cache, serializedArr }) => {
   return null
 }
 
-/*
-type Props = {
-  children: ({
-    css: (...args: any) => string,
-    cx: (...args: Array<ClassNameArg>) => string,
-    theme: Object
-  }) => React.Node
-} */
+export interface ClassNamesContent {
+  css(template: TemplateStringsArray, ...args: Array<CSSInterpolation>): string
+  css(...args: Array<CSSInterpolation>): string
+  cx(...args: Array<ClassNamesArg>): string
+  theme: Theme
+}
+
+export interface ClassNamesProps {
+  children(content: ClassNamesContent): React.ReactNode
+}
 
-export const ClassNames /*: React.AbstractComponent<Props>*/ =
-  /* #__PURE__ */ withEmotionCache((props, cache) => {
+export const ClassNames = /* #__PURE__ */ withEmotionCache<ClassNamesProps>(
+  (props, cache) => {
     let hasRendered = false
-    let serializedArr = []
+    let serializedArr: SerializedStyles[] = []
 
-    let css = (...args /*: Array<any> */) => {
+    let css: ClassNamesContent['css'] = (...args) => {
       if (hasRendered && isDevelopment) {
         throw new Error('css can only be used during render')
       }
@@ -142,7 +152,7 @@ export const ClassNames /*: React.AbstractComponent<Props>*/ =
       registerStyles(cache, serialized, false)
       return `${cache.key}-${serialized.name}`
     }
-    let cx = (...args /*: Array<ClassNameArg>*/) => {
+    let cx = (...args: Array<ClassNamesArg>) => {
       if (hasRendered && isDevelopment) {
         throw new Error('cx can only be used during render')
       }
@@ -162,7 +172,8 @@ export const ClassNames /*: React.AbstractComponent<Props>*/ =
         {ele}
       </>
     )
-  })
+  }
+)
 
 if (isDevelopment) {
   ClassNames.displayName = 'EmotionClassNames'