Add types

Closes GH-20.

Reviewed-by: Junyoung Choi <fluke8259@gmail.com>
Reviewed-by: Remco Haszing <remcohaszing@gmail.com>
Reviewed-by: Titus Wormer <tituswormer@gmail.com>

package.json

@@ -32,17 +32,25 @@
     "David Clark <dclark@mapbox.com>",
     "Tucker Whitehouse <Tucker.Whitehouse@LibertyMutual.com>",
     "kthjm <toxictoxer@gmail.com>",
-    "Artem Sapegin <artem@sapegin.ru>"
+    "Artem Sapegin <artem@sapegin.ru>",
+    "Christian Murphy <christian.murphy.42@gmail.com>"
   ],
   "files": [
-    "index.js"
+    "index.js",
+    "types/index.d.ts"
   ],
+  "types": "types/index.d.ts",
   "dependencies": {
     "@mapbox/hast-util-table-cell-style": "^0.1.3",
-    "hast-to-hyperscript": "^8.0.0"
+    "hast-to-hyperscript": "^9.0.0"
   },
   "devDependencies": {
+    "@types/hyperscript": "0.0.4",
+    "@types/react": "^16.9.35",
+    "@types/virtual-dom": "^2.1.0",
+    "dtslint": "^3.6.3",
     "hastscript": "^5.0.0",
+    "hyperscript": "^2.0.2",
     "nyc": "^15.0.0",
     "prettier": "^2.0.0",
     "react": "^16.0.0",
@@ -53,13 +61,15 @@
     "tape": "^4.0.0",
     "unified": "^9.0.0",
     "unist-builder": "^2.0.0",
+    "vue": "^2.6.11",
     "xo": "^0.28.0"
   },
   "scripts": {
     "format": "remark . -qfo && prettier --write \"**/*.js\" && xo --fix",
     "test-api": "node test",
     "test-coverage": "nyc --reporter lcov tape test.js",
-    "test": "npm run format && npm run test-coverage"
+    "test-types": "dtslint types",
+    "test": "npm run format && npm run test-coverage && npm run test-types"
   },
   "nyc": {
     "check-coverage": true,

types/index.d.ts

@@ -0,0 +1,47 @@
+// Minimum TypeScript Version: 3.4
+
+import {Transformer} from 'unified'
+import {Prefix, CreateElementLike} from 'hast-to-hyperscript'
+
+declare namespace rehypeReact {
+  type FragmentLike<T> = (props: any) => T | null
+
+  type ComponentLike<T> = (props: {[prop: string]: unknown}) => T | null
+
+  interface Options<H extends CreateElementLike> {
+    /**
+     * How to create elements or components.
+     * You should typically pass `React.createElement`
+     */
+    createElement: H
+
+    /**
+     * Create fragments instead of an outer `<div>` if available
+     * You should typically pass `React.Fragment`
+     */
+    Fragment?: FragmentLike<ReturnType<H>>
+
+    /**
+     * Override default elements (such as `<a>`, `<p>`, etcetera) by passing an object mapping tag names to components
+     */
+    components?: {
+      [element: string]: ComponentLike<ReturnType<H>>
+    }
+
+    /**
+     * React key prefix
+     *
+     * @defaultValue 'h-'
+     */
+    prefix?: Prefix
+  }
+}
+
+/**
+ * Rehype plugin to transform to React
+ */
+declare function rehypeReact<H extends CreateElementLike>(
+  options: rehypeReact.Options<H>
+): Transformer
+
+export = rehypeReact

types/rehype-react-test.tsx

@@ -0,0 +1,55 @@
+import * as unified from 'unified'
+import * as rehypeToReact from 'rehype-react'
+import * as React from 'react'
+import {h as virtualDomCreateElement} from 'virtual-dom'
+import * as hyperscriptCreateElement from 'hyperscript'
+import Vue from 'vue'
+
+// Create element must be provided
+unified().use(rehypeToReact) // $ExpectError
+unified().use(rehypeToReact, {}) // $ExpectError
+
+// multiple frameworks providing createElement can be used
+unified().use(rehypeToReact, {createElement: React.createElement})
+unified().use(rehypeToReact, {createElement: virtualDomCreateElement})
+unified().use(rehypeToReact, {createElement: hyperscriptCreateElement})
+unified().use(rehypeToReact, {createElement: new Vue().$createElement})
+unified().use(rehypeToReact, {
+  createElement: (name: number) => name // $ExpectError
+})
+
+// Prefix, fragment, and components are optional
+unified().use(rehypeToReact, {
+  createElement: React.createElement,
+  prefix: 'h'
+})
+
+unified().use(rehypeToReact, {
+  createElement: React.createElement,
+  Fragment: React.Fragment
+})
+
+unified().use(rehypeToReact, {
+  createElement: React.createElement,
+  components: {
+    a: () => <a>example</a>
+  }
+})
+
+unified().use(rehypeToReact, {
+  createElement: React.createElement,
+  components: {
+    div: () => <>example</>
+  }
+})
+
+// Mismatch between framework of createElement and components or Fragment should fail
+unified().use(rehypeToReact, {
+  createElement: virtualDomCreateElement,
+  // prettier-ignore typescript versions can disagree where error happens, squish statement so they agree
+  components: {a: () => <a>example</a>} // $ExpectError
+})
+unified().use(rehypeToReact, {
+  createElement: virtualDomCreateElement,
+  Fragment: () => <a>example</a> // $ExpectError
+})

types/tsconfig.json

@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "lib": ["es2015", "DOM"],
+    "strict": true,
+    "baseUrl": ".",
+    "paths": {
+      "rehype-react": ["index.d.ts"]
+    },
+    "jsx": "react"
+  }
+}

types/tslint.json

@@ -0,0 +1,8 @@
+{
+  "extends": "dtslint/dtslint.json",
+  "rules": {
+    "semicolon": false,
+    "whitespace": false,
+    "no-unnecessary-generics": false
+  }
+}