diff --git a/.github/workflows/bb.yml b/.github/workflows/bb.yml
index 291ab09..0198fc3 100644
--- a/.github/workflows/bb.yml
+++ b/.github/workflows/bb.yml
@@ -2,7 +2,7 @@ name: bb
 on:
   issues:
     types: [opened, reopened, edited, closed, labeled, unlabeled]
-  pull_request:
+  pull_request_target:
     types: [opened, reopened, edited, closed, labeled, unlabeled]
 jobs:
   main:
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index fe284ad..69924a4 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -17,5 +17,5 @@ jobs:
     strategy:
       matrix:
         node:
-          - lts/erbium
+          - lts/fermium
           - node
diff --git a/.npmrc b/.npmrc
index 43c97e7..9951b11 100644
--- a/.npmrc
+++ b/.npmrc
@@ -1 +1,2 @@
 package-lock=false
+ignore-scripts=true
diff --git a/index.js b/index.js
index 90a4fc9..f33ac57 100644
--- a/index.js
+++ b/index.js
@@ -1,6 +1,8 @@
 /**
- * @typedef {import('./lib/index.js').XChild}} Child Acceptable child value
- * @typedef {import('./lib/index.js').XAttributes}} Attributes Acceptable attributes value.
+ * @typedef {import('./lib/index.js').XChild}} Child
+ *   Acceptable child value
+ * @typedef {import('./lib/index.js').XAttributes}} Attributes
+ *   Acceptable attributes value.
  */
 
 export {x} from './lib/index.js'
diff --git a/lib/index.js b/lib/index.js
index 6af9859..71cdc57 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -8,12 +8,12 @@
  * @typedef {{[attribute: string]: XValue}} XAttributes Attributes to support JS primitive types
  *
  * @typedef {string|number|null|undefined} XPrimitiveChild
- * @typedef {Array.<Node|XPrimitiveChild>} XArrayChild
+ * @typedef {Array<Node|XPrimitiveChild>} XArrayChild
  * @typedef {Node|XPrimitiveChild|XArrayChild} XChild
- * @typedef {import('./jsx-classic').Element} x.JSX.Element
- * @typedef {import('./jsx-classic').IntrinsicAttributes} x.JSX.IntrinsicAttributes
- * @typedef {import('./jsx-classic').IntrinsicElements} x.JSX.IntrinsicElements
- * @typedef {import('./jsx-classic').ElementChildrenAttribute} x.JSX.ElementChildrenAttribute
+ * @typedef {import('./jsx-classic.js').Element} x.JSX.Element
+ * @typedef {import('./jsx-classic.js').IntrinsicAttributes} x.JSX.IntrinsicAttributes
+ * @typedef {import('./jsx-classic.js').IntrinsicElements} x.JSX.IntrinsicElements
+ * @typedef {import('./jsx-classic.js').ElementChildrenAttribute} x.JSX.ElementChildrenAttribute
  */
 
 /**
@@ -27,9 +27,9 @@ export const x =
   /**
    * @type {{
    *   (): Root
-   *   (name: null|undefined, ...children: XChild[]): Root
-   *   (name: string, attributes: XAttributes, ...children: XChild[]): Element
-   *   (name: string, ...children: XChild[]): Element
+   *   (name: null|undefined, ...children: Array<XChild>): Root
+   *   (name: string, attributes: XAttributes, ...children: Array<XChild>): Element
+   *   (name: string, ...children: Array<XChild>): Element
    * }}
    */
   (
@@ -38,24 +38,25 @@ export const x =
      *
      * @param {string|null} [name]
      * @param {XAttributes|XChild} [attributes]
-     * @param {XChild[]} children
+     * @param {Array<XChild>} children
      * @returns {XResult}
      */
     function (name, attributes, ...children) {
-      var index = -1
+      let index = -1
       /** @type {XResult} */
-      var node
-      /** @type {string} */
-      var key
+      let node
 
       if (name === undefined || name === null) {
         node = {type: 'root', children: []}
-        // @ts-ignore Root builder doesn’t accept attributes.
+        // @ts-expect-error Root builder doesn’t accept attributes.
         children.unshift(attributes)
       } else if (typeof name === 'string') {
         node = {type: 'element', name, attributes: {}, children: []}
 
         if (isAttributes(attributes)) {
+          /** @type {string} */
+          let key
+
           for (key in attributes) {
             // Ignore nullish and NaN values.
             if (
@@ -64,7 +65,7 @@ export const x =
               (typeof attributes[key] !== 'number' ||
                 !Number.isNaN(attributes[key]))
             ) {
-              // @ts-ignore Pretty sure we just set it.
+              // @ts-expect-error Pretty sure we just set it.
               node.attributes[key] = String(attributes[key])
             }
           }
@@ -85,11 +86,11 @@ export const x =
   )
 
 /**
- * @param {Array.<Child>} nodes
+ * @param {Array<Child>} nodes
  * @param {XChild} value
  */
 function addChild(nodes, value) {
-  var index = -1
+  let index = -1
 
   if (value === undefined || value === null) {
     // Empty.
diff --git a/lib/jsx-automatic.d.ts b/lib/jsx-automatic.d.ts
index 3c45020..ac742b3 100644
--- a/lib/jsx-automatic.d.ts
+++ b/lib/jsx-automatic.d.ts
@@ -1,3 +1,4 @@
+/* eslint-disable-next-line @typescript-eslint/consistent-type-imports -- fix in major */
 import {XAttributes, XChild, XResult} from './index.js'
 
 export namespace JSX {
@@ -11,6 +12,8 @@ export namespace JSX {
    */
   type IntrinsicAttributes = never
 
+  /* eslint-disable @typescript-eslint/consistent-type-definitions -- interfaces are required here */
+
   /**
    * This defines the prop types for known elements.
    *
@@ -39,4 +42,6 @@ export namespace JSX {
      */
     children?: never
   }
+
+  /* eslint-enable @typescript-eslint/consistent-type-definitions */
 }
diff --git a/lib/jsx-classic.d.ts b/lib/jsx-classic.d.ts
index 1e1e0a0..53de7ad 100644
--- a/lib/jsx-classic.d.ts
+++ b/lib/jsx-classic.d.ts
@@ -1,3 +1,4 @@
+/* eslint-disable-next-line @typescript-eslint/consistent-type-imports -- fix in major */
 import {XAttributes, XChild, XResult} from './index.js'
 
 /**
@@ -16,6 +17,8 @@ export type Element = XResult
  */
 export type IntrinsicAttributes = never
 
+/* eslint-disable @typescript-eslint/consistent-type-definitions -- interfaces are required here */
+
 /**
  * This defines the prop types for known elements.
  *
@@ -44,3 +47,5 @@ export interface ElementChildrenAttribute {
    */
   [children]?: never
 }
+
+/* eslint-enable @typescript-eslint/consistent-type-definitions */
diff --git a/lib/runtime.js b/lib/runtime.js
index b608d4e..51a71a8 100644
--- a/lib/runtime.js
+++ b/lib/runtime.js
@@ -34,7 +34,7 @@ export const jsx =
      * @returns {XResult}
      */
     function (name, props) {
-      var {children, ...properties} = props
+      const {children, ...properties} = props
       return name === null ? x(name, children) : x(name, properties, children)
     }
   )
diff --git a/package.json b/package.json
index 8ad5e34..3678641 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "xastscript",
-  "version": "3.0.0",
+  "version": "3.0.1",
   "description": "xast utility to create trees",
   "license": "MIT",
   "keywords": [
@@ -32,7 +32,9 @@
   "files": [
     "lib/",
     "index.d.ts",
-    "index.js"
+    "index.js",
+    "jsx-runtime.d.ts",
+    "jsx-runtime.js"
   ],
   "exports": {
     ".": "./index.js",
@@ -48,20 +50,19 @@
     "@babel/plugin-transform-react-jsx": "^7.0.0",
     "@types/babel__core": "^7.0.0",
     "@types/tape": "^4.0.0",
-    "astring": "^1.0.0",
-    "buble": "^0.20.0",
     "c8": "^7.0.0",
     "estree-util-build-jsx": "^2.0.0",
+    "estree-util-to-js": "^1.0.0",
     "prettier": "^2.0.0",
-    "remark-cli": "^9.0.0",
-    "remark-preset-wooorm": "^8.0.0",
+    "remark-cli": "^11.0.0",
+    "remark-preset-wooorm": "^9.0.0",
     "rimraf": "^3.0.0",
     "tape": "^5.0.0",
-    "tsd": "^0.14.0",
+    "tsd": "^0.23.0",
     "type-coverage": "^2.0.0",
     "typescript": "^4.0.0",
     "unist-builder": "^3.0.0",
-    "xo": "^0.39.0"
+    "xo": "^0.52.0"
   },
   "scripts": {
     "prepack": "npm run build && npm run format",
@@ -81,11 +82,7 @@
     "trailingComma": "none"
   },
   "xo": {
-    "prettier": true,
-    "rules": {
-      "no-var": "off",
-      "prefer-arrow-callback": "off"
-    }
+    "prettier": true
   },
   "remarkConfig": {
     "plugins": [
diff --git a/readme.md b/readme.md
index 0930dfd..c0d62db 100644
--- a/readme.md
+++ b/readme.md
@@ -8,20 +8,62 @@
 [![Backers][backers-badge]][collective]
 [![Chat][chat-badge]][chat]
 
-**[xast][]** utility to create XML *[trees][tree]* (like [`hastscript`][h] for
-**[hast][]** and [`unist-builder`][u] for **[unist][]**).
+[xast][] utility to create trees with ease.
 
-## Install
+## Contents
+
+*   [What is this?](#what-is-this)
+*   [When should I use this?](#when-should-i-use-this)
+*   [Install](#install)
+*   [Use](#use)
+*   [API](#api)
+    *   [`x(name?[, attributes][, …children])`](#xname-attributes-children)
+*   [JSX](#jsx)
+*   [Types](#types)
+*   [Compatibility](#compatibility)
+*   [Security](#security)
+*   [Related](#related)
+*   [Contribute](#contribute)
+*   [License](#license)
+
+## What is this?
+
+This package is a hyperscript interface (like `createElement` from React and
+such) to help with creating xast trees.
+
+## When should I use this?
 
-This package is [ESM only](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c):
-Node 12+ is needed to use it and it must be `import`ed instead of `require`d.
+You can use this utility in your project when you generate xast syntax trees
+with code.
+It helps because it replaces most of the repetition otherwise needed in a syntax
+tree with function calls.
 
-[npm][]:
+You can instead use [`unist-builder`][u] when creating any unist nodes and
+[`hastscript`][h] when creating hast (HTML) nodes.
+
+## Install
+
+This package is [ESM only][esm].
+In Node.js (version 12.20+, 14.14+, 16.0+, 18.0+), install with [npm][]:
 
 ```sh
 npm install xastscript
 ```
 
+In Deno with [`esm.sh`][esmsh]:
+
+```js
+import {x} from 'https://esm.sh/xastscript@3'
+```
+
+In browsers with [`esm.sh`][esmsh]:
+
+```html
+<script type="module">
+  import {x} from 'https://esm.sh/xastscript@3?bundle'
+</script>
+```
+
 ## Use
 
 ```js
@@ -145,9 +187,16 @@ Yields:
 
 ## API
 
+This package exports the identifier `x`.
+There is no default export.
+
+The export map supports the automatic JSX runtime.
+You can pass `xastscript` to your build tool (TypeScript, Babel, SWC) as with
+an `importSource` option or similar.
+
 ### `x(name?[, attributes][, …children])`
 
-Create XML *[trees][tree]* in **[xast][]**.
+Create [xast][] trees.
 
 ##### Signatures
 
@@ -166,7 +215,8 @@ When nullish, a [`Root`][root] is built instead.
 
 ###### `attributes`
 
-Map of attributes (`Object.<*>`, optional).
+Map of attributes (`Record<string, string|number|boolean|null|undefined>`,
+optional).
 Nullish (`null` or `undefined`) or `NaN` values are ignored, other values are
 turned to strings.
 
@@ -176,10 +226,10 @@ Cannot be omitted when building an [`Element`][element] if the first child is a
 
 ###### `children`
 
-(Lists of) children (`string`, `number`, `Node`, `Array.<children>`, optional).
+(Lists of) children (`string`, `number`, `Node`, `Array<children>`, optional).
 When strings or numbers are encountered, they are mapped to [`Text`][text]
 nodes.
-If a [`Root`][root] node is given, its children are used instead.
+If a [`Root`][root] node is encountered, its children are used instead.
 
 ##### Returns
 
@@ -187,12 +237,15 @@ If a [`Root`][root] node is given, its children are used instead.
 
 ## JSX
 
-`xastscript` can be used as a pragma for JSX.
+`xastscript` can be used with JSX.
+Either use the automatic runtime set to `xastscript` or import `x` yourself and
+define it as the pragma (plus set the fragment to `null`).
+
 The example above (omitting the second) can then be written like so:
 
 ```jsx
+/** @jsxImportSource x */
 import {u} from 'unist-builder'
-import {x} from 'xastscript'
 
 console.log(
   <album id={123}>
@@ -214,17 +267,14 @@ console.log(
 )
 ```
 
-Note that you must still import `xastscript` yourself and configure your
-JavaScript compiler to use the identifier you assign it to as a pragma (and
-pass `null` for fragments).
-
-For [bublé][], this can be done by setting `jsx: 'x'` and `jsxFragment: 'null'`
-(note that `jsxFragment` is currently only available on the API, not the CLI).
+You can use [`estree-util-build-jsx`][estree-util-build-jsx] to compile JSX
+away.
 
-For [Babel][], use [`@babel/plugin-transform-react-jsx`][babel-jsx] (in classic
-mode), and pass `pragma: 'x'` and `pragmaFrag: 'null'`.
-
-Babel also lets you configure this in a script:
+For [Babel][], use [`@babel/plugin-transform-react-jsx`][babel-jsx] and either
+pass `pragma: 'x'` and `pragmaFrag: 'null'`, or pass `importSource:
+'xastscript'`.
+Alternatively, Babel also lets you configure this with a comment:
+Babel also lets you configure this from code:
 
 ```jsx
 /** @jsx x @jsxFrag null */
@@ -236,16 +286,20 @@ console.log(<music />)
 For [TypeScript][], this can be done by setting `"jsx": "react"`,
 `"jsxFactory": "x"`, and `"jsxFragmentFactory": "null"` in the compiler options.
 For more details on configuring JSX for TypeScript, see the
-[TypeScript JSX handbook page][].
+[TypeScript JSX handbook page][typescript-jsx].
+TypeScript also lets you configure this from code as shown with Babel above.
 
-TypeScript also lets you configure this in a script:
+## Types
 
-```tsx
-/** @jsx x @jsxFrag null */
-import {x} from 'xastscript'
+This package is fully typed with [TypeScript][].
+It exports the additional types `Child` and `Attributes`.
 
-console.log(<music />)
-```
+## Compatibility
+
+Projects maintained by the unified collective are compatible with all maintained
+versions of Node.js.
+As of now, that is Node.js 12.20+, 14.14+, 16.0+, and 18.0+.
+Our projects sometimes work with older versions, but this is not guaranteed.
 
 ## Security
 
@@ -254,20 +308,20 @@ XML can be a dangerous language: don’t trust user-provided data.
 ## Related
 
 *   [`unist-builder`][u]
-    — Create any unist tree
+    — create any unist tree
 *   [`hastscript`][h]
-    — Create a **[hast][]** (HTML or SVG) unist tree
+    — create a hast tree
 *   [`xast-util-to-xml`](https://github.com/syntax-tree/xast-util-to-xml)
-    — Serialize nodes to XML
+    — serialize xast as XML
 *   [`xast-util-from-xml`](https://github.com/syntax-tree/xast-util-from-xml)
-    — Parse from XML
+    — parse xast from XML
 *   [`hast-util-to-xast`](https://github.com/syntax-tree/hast-util-to-xast)
-    — Transform hast (html, svg) to xast (xml)
+    — transform hast to xast
 
 ## Contribute
 
-See [`contributing.md` in `syntax-tree/.github`][contributing] for ways to get
-started.
+See [`contributing.md`][contributing] in [`syntax-tree/.github`][health] for
+ways to get started.
 See [`support.md`][support] for ways to get help.
 
 This project has a [code of conduct][coc].
@@ -308,24 +362,26 @@ abide by its terms.
 
 [npm]: https://docs.npmjs.com/cli/install
 
+[esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c
+
+[esmsh]: https://esm.sh
+
+[typescript]: https://www.typescriptlang.org
+
 [license]: license
 
 [author]: https://wooorm.com
 
-[contributing]: https://github.com/syntax-tree/.github/blob/HEAD/contributing.md
+[health]: https://github.com/syntax-tree/.github
 
-[support]: https://github.com/syntax-tree/.github/blob/HEAD/support.md
+[contributing]: https://github.com/syntax-tree/.github/blob/main/contributing.md
 
-[coc]: https://github.com/syntax-tree/.github/blob/HEAD/code-of-conduct.md
+[support]: https://github.com/syntax-tree/.github/blob/main/support.md
 
-[unist]: https://github.com/syntax-tree/unist
-
-[hast]: https://github.com/syntax-tree/hast
+[coc]: https://github.com/syntax-tree/.github/blob/main/code-of-conduct.md
 
 [xast]: https://github.com/syntax-tree/xast
 
-[tree]: https://github.com/syntax-tree/unist#tree
-
 [node]: https://github.com/syntax-tree/unist#node
 
 [root]: https://github.com/syntax-tree/xast#root
@@ -338,12 +394,10 @@ abide by its terms.
 
 [h]: https://github.com/syntax-tree/hastscript
 
-[bublé]: https://github.com/Rich-Harris/buble
-
 [babel]: https://github.com/babel/babel
 
 [babel-jsx]: https://github.com/babel/babel/tree/main/packages/babel-plugin-transform-react-jsx
 
-[typescript]: https://www.typescriptlang.org
+[typescript-jsx]: https://www.typescriptlang.org/docs/handbook/jsx.html
 
-[typescript jsx handbook page]: https://www.typescriptlang.org/docs/handbook/jsx.html
+[estree-util-build-jsx]: https://github.com/syntax-tree/estree-util-build-jsx
diff --git a/script/generate-jsx.js b/script/generate-jsx.js
index 04921dd..8484b87 100644
--- a/script/generate-jsx.js
+++ b/script/generate-jsx.js
@@ -1,46 +1,52 @@
-import fs from 'fs'
-import path from 'path'
+import fs from 'node:fs'
+import path from 'node:path'
 import babel from '@babel/core'
 import {Parser} from 'acorn'
 import acornJsx from 'acorn-jsx'
-import {generate} from 'astring'
+import {toJs} from 'estree-util-to-js'
 import {buildJsx} from 'estree-util-build-jsx'
 
-var doc = String(fs.readFileSync(path.join('test', 'jsx.jsx')))
+const doc = String(fs.readFileSync(path.join('test', 'jsx.jsx')))
 
 fs.writeFileSync(
   path.join('test', 'jsx-build-jsx-classic.js'),
-  generate(
+  toJs(
+    // @ts-expect-error it’s a program.
     buildJsx(
-      // @ts-ignore Acorn nodes are assignable to ESTree nodes.
+      // @ts-expect-error Acorn nodes are assignable to ESTree nodes.
       Parser.extend(acornJsx()).parse(
         doc.replace(/'name'/, "'jsx (estree-util-build-jsx, classic)'"),
+        // Note: different npms resolve this differently, so it may break or work, hence the ignore.
         // @ts-ignore Hush, `2021` is fine.
         {sourceType: 'module', ecmaVersion: 2021}
       ),
       {pragma: 'x', pragmaFrag: 'null'}
     )
-  )
+    // @ts-expect-error Some bug in `to-js`
+  ).value
 )
 
 fs.writeFileSync(
   path.join('test', 'jsx-build-jsx-automatic.js'),
-  generate(
+  toJs(
+    // @ts-expect-error it’s a program.
     buildJsx(
-      // @ts-ignore Acorn nodes are assignable to ESTree nodes.
+      // @ts-expect-error Acorn nodes are assignable to ESTree nodes.
       Parser.extend(acornJsx()).parse(
         doc.replace(/'name'/, "'jsx (estree-util-build-jsx, automatic)'"),
+        // Note: different npms resolve this differently, so it may break or work, hence the ignore.
         // @ts-ignore Hush, `2021` is fine.
         {sourceType: 'module', ecmaVersion: 2021}
       ),
       {runtime: 'automatic', importSource: '.'}
     )
-  ).replace(/\/jsx-runtime(?=["'])/g, './lib/runtime.js')
+    // @ts-expect-error Some bug in `to-js`
+  ).value.replace(/\/jsx-runtime(?=["'])/g, './lib/runtime.js')
 )
 
 fs.writeFileSync(
   path.join('test', 'jsx-babel-classic.js'),
-  // @ts-ignore Result always given.
+  // @ts-expect-error Result always given.
   babel.transform(doc.replace(/'name'/, "'jsx (babel, classic)'"), {
     plugins: [
       ['@babel/plugin-transform-react-jsx', {pragma: 'x', pragmaFrag: 'null'}]
@@ -50,7 +56,7 @@ fs.writeFileSync(
 
 fs.writeFileSync(
   path.join('test', 'jsx-babel-automatic.js'),
-  // @ts-ignore Result always given.
+  // @ts-expect-error Result always given.
   babel
     .transformSync(doc.replace(/'name'/, "'jsx (babel, automatic)'"), {
       plugins: [
diff --git a/test-d/automatic.tsx b/test-d/automatic.tsx
index 7203678..dc3f4e8 100644
--- a/test-d/automatic.tsx
+++ b/test-d/automatic.tsx
@@ -2,7 +2,7 @@
 /* @jsxImportSource .. */
 
 import {expectType, expectError} from 'tsd'
-import {Root, Element} from 'xast'
+import type {Root, Element} from 'xast'
 import {x} from '../index.js'
 import {Fragment, jsx, jsxs} from '../jsx-runtime.js'
 
diff --git a/test-d/classic.tsx b/test-d/classic.tsx
index c880686..1470076 100644
--- a/test-d/classic.tsx
+++ b/test-d/classic.tsx
@@ -1,7 +1,7 @@
 /* @jsx x */
 /* @jsxFrag null */
 import {expectType, expectError} from 'tsd'
-import {Root, Element} from 'xast'
+import type {Root, Element} from 'xast'
 import {x} from '../index.js'
 
 type Result = Element | Root
diff --git a/test-d/index.tsx b/test-d/index.tsx
index a62cace..1c62379 100644
--- a/test-d/index.tsx
+++ b/test-d/index.tsx
@@ -1,5 +1,5 @@
 import {expectType, expectError} from 'tsd'
-import {Root, Element} from 'xast'
+import type {Root, Element} from 'xast'
 import {x} from '../index.js'
 
 expectType<Root>(x())
diff --git a/test/core.js b/test/core.js
index 7e220c4..4c1225c 100644
--- a/test/core.js
+++ b/test/core.js
@@ -1,7 +1,7 @@
 import test from 'tape'
 import {x} from '../index.js'
 
-test('xastscript', function (t) {
+test('xastscript', (t) => {
   t.equal(typeof x, 'function', 'should expose a function')
 
   t.deepEqual(
@@ -11,8 +11,8 @@ test('xastscript', function (t) {
   )
 
   t.throws(
-    function () {
-      // @ts-ignore runtime.
+    () => {
+      // @ts-expect-error runtime.
       x(1)
     },
     /Expected element name, got `1`/,
@@ -69,7 +69,7 @@ test('xastscript', function (t) {
   )
 
   t.deepEqual(
-    // @ts-ignore Deeply nested children are not typed.
+    // @ts-expect-error Deeply nested children are not typed.
     x('y', {}, [[[x('a')]], [[[[x('b')]], x('c')]]]),
     {
       type: 'element',
@@ -119,8 +119,8 @@ test('xastscript', function (t) {
   )
 
   t.throws(
-    function () {
-      // @ts-ignore runtime.
+    () => {
+      // @ts-expect-error runtime.
       x('y', {}, {})
     },
     /Expected node, nodes, string, got `\[object Object]`/,
diff --git a/test/jsx.jsx b/test/jsx.jsx
index 7774e5b..3b3397f 100644
--- a/test/jsx.jsx
+++ b/test/jsx.jsx
@@ -2,12 +2,12 @@ import test from 'tape'
 import {u} from 'unist-builder'
 import {x} from '../index.js'
 
-test('name', function (t) {
+test('name', (t) => {
   t.deepEqual(<a />, x('a'), 'should support a self-closing element')
 
   t.deepEqual(<a>b</a>, x('a', 'b'), 'should support a value as a child')
 
-  var A = 'a'
+  const A = 'a'
 
   t.deepEqual(<A />, x(A), 'should support an uppercase tag name')
 
@@ -39,7 +39,7 @@ test('name', function (t) {
     'should support a fragment with an expression'
   )
 
-  var com = {acme: {a: 'A', b: 'B'}}
+  const com = {acme: {a: 'A', b: 'B'}}
 
   t.deepEqual(
     <com.acme.a />,
@@ -71,7 +71,7 @@ test('name', function (t) {
     'should support expression value attributes'
   )
 
-  var props = {a: 1, b: 2}
+  const props = {a: 1, b: 2}
 
   t.deepEqual(
     <a {...props} />,
@@ -96,7 +96,7 @@ test('name', function (t) {
     'should support a fragment in an element (#1)'
   )
 
-  var dl = [
+  const dl = [
     ['Firefox', 'A red panda.'],
     ['Chrome', 'A chemical element.']
   ]
diff --git a/tsconfig.json b/tsconfig.json
index 60106cb..ec45143 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -19,6 +19,7 @@
     "emitDeclarationOnly": true,
     "allowSyntheticDefaultImports": true,
     "skipLibCheck": true,
-    "strictNullChecks": true
+    "strictNullChecks": true,
+    "strict": true
   }
 }