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..fb63387 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -7,15 +7,15 @@ jobs:
     name: ${{matrix.node}}
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: dcodeIO/setup-node-nvm@master
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
         with:
           node-version: ${{matrix.node}}
       - run: npm install
       - run: npm test
-      - uses: codecov/codecov-action@v1
+      - uses: codecov/codecov-action@v3
     strategy:
       matrix:
         node:
-          - lts/erbium
+          - lts/gallium
           - 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 138193a..8674f30 100644
--- a/index.js
+++ b/index.js
@@ -1,55 +1,5 @@
 /**
- * @typedef Options
- * @property {boolean} [includeImageAlt=true]
+ * @typedef {import('./lib/index.js').Options} Options
  */
 
-/**
- * Get the text content of a node.
- * Prefer the node’s plain-text fields, otherwise serialize its children,
- * and if the given value is an array, serialize the nodes in it.
- *
- * @param {unknown} node
- * @param {Options} [options]
- * @returns {string}
- */
-export function toString(node, options) {
-  var {includeImageAlt = true} = options || {}
-  return one(node, includeImageAlt)
-}
-
-/**
- * @param {unknown} node
- * @param {boolean} includeImageAlt
- * @returns {string}
- */
-function one(node, includeImageAlt) {
-  return (
-    (node &&
-      typeof node === 'object' &&
-      // @ts-ignore looks like a literal.
-      (node.value ||
-        // @ts-ignore looks like an image.
-        (includeImageAlt ? node.alt : '') ||
-        // @ts-ignore looks like a parent.
-        ('children' in node && all(node.children, includeImageAlt)) ||
-        (Array.isArray(node) && all(node, includeImageAlt)))) ||
-    ''
-  )
-}
-
-/**
- * @param {Array.<unknown>} values
- * @param {boolean} includeImageAlt
- * @returns {string}
- */
-function all(values, includeImageAlt) {
-  /** @type {Array.<string>} */
-  var result = []
-  var index = -1
-
-  while (++index < values.length) {
-    result[index] = one(values[index], includeImageAlt)
-  }
-
-  return result.join('')
-}
+export {toString} from './lib/index.js'
diff --git a/lib/index.js b/lib/index.js
new file mode 100644
index 0000000..d0e7314
--- /dev/null
+++ b/lib/index.js
@@ -0,0 +1,84 @@
+/**
+ * @typedef {import('mdast').Root|import('mdast').Content} Node
+ *
+ * @typedef Options
+ *   Configuration (optional).
+ * @property {boolean | null | undefined} [includeImageAlt=true]
+ *   Whether to use `alt` for `image`s.
+ */
+
+/**
+ * Get the text content of a node or list of nodes.
+ *
+ * Prefers the node’s plain-text fields, otherwise serializes its children,
+ * and if the given value is an array, serialize the nodes in it.
+ *
+ * @param {unknown} value
+ *   Thing to serialize, typically `Node`.
+ * @param {Options | null | undefined} [options]
+ *   Configuration (optional).
+ * @returns {string}
+ *   Serialized `value`.
+ */
+export function toString(value, options) {
+  const includeImageAlt = (options || {}).includeImageAlt
+  return one(
+    value,
+    typeof includeImageAlt === 'boolean' ? includeImageAlt : true
+  )
+}
+
+/**
+ * One node or several nodes.
+ *
+ * @param {unknown} value
+ *   Thing to serialize.
+ * @param {boolean} includeImageAlt
+ *   Include image `alt`s.
+ * @returns {string}
+ *   Serialized node.
+ */
+function one(value, includeImageAlt) {
+  return (
+    (node(value) &&
+      (('value' in value && value.value) ||
+        (includeImageAlt && 'alt' in value && value.alt) ||
+        ('children' in value && all(value.children, includeImageAlt)))) ||
+    (Array.isArray(value) && all(value, includeImageAlt)) ||
+    ''
+  )
+}
+
+/**
+ * Serialize a list of nodes.
+ *
+ * @param {Array<unknown>} values
+ *   Thing to serialize.
+ * @param {boolean} includeImageAlt
+ *   Include image `alt`s.
+ * @returns {string}
+ *   Serialized nodes.
+ */
+function all(values, includeImageAlt) {
+  /** @type {Array<string>} */
+  const result = []
+  let index = -1
+
+  while (++index < values.length) {
+    result[index] = one(values[index], includeImageAlt)
+  }
+
+  return result.join('')
+}
+
+/**
+ * Check if `value` looks like a node.
+ *
+ * @param {unknown} value
+ *   Thing.
+ * @returns {value is Node}
+ *   Whether `value` is a node.
+ */
+function node(value) {
+  return Boolean(value && typeof value === 'object')
+}
diff --git a/package.json b/package.json
index 03ef400..10edf20 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "mdast-util-to-string",
-  "version": "3.1.0",
+  "version": "3.1.1",
   "description": "mdast utility to get the plain text content of a node",
   "license": "MIT",
   "keywords": [
@@ -29,27 +29,30 @@
   "main": "index.js",
   "types": "index.d.ts",
   "files": [
+    "lib/",
     "index.d.ts",
     "index.js"
   ],
+  "dependencies": {
+    "@types/mdast": "^3.0.0"
+  },
   "devDependencies": {
-    "@types/tape": "^4.0.0",
+    "@types/node": "^18.0.0",
     "c8": "^7.0.0",
     "prettier": "^2.0.0",
-    "remark-cli": "^9.0.0",
-    "remark-preset-wooorm": "^8.0.0",
-    "rimraf": "^3.0.0",
+    "remark-cli": "^11.0.0",
+    "remark-preset-wooorm": "^9.0.0",
     "tape": "^5.0.0",
     "type-coverage": "^2.0.0",
     "typescript": "^4.0.0",
-    "xo": "^0.39.0"
+    "xo": "^0.53.0"
   },
   "scripts": {
     "prepack": "npm run build && npm run format",
-    "build": "rimraf \"*.d.ts\" && tsc && type-coverage",
+    "build": "tsc --build --clean && tsc --build && type-coverage",
     "format": "remark . -qfo && prettier . -w --loglevel warn && xo --fix",
-    "test-api": "node test.js",
-    "test-coverage": "c8 --check-coverage --branches 100 --functions 100 --lines 100 --statements 100 --reporter lcov node test.js",
+    "test-api": "node --conditions development test.js",
+    "test-coverage": "c8 --check-coverage --100 --reporter lcov npm run test-api",
     "test": "npm run build && npm run format && npm run test-coverage"
   },
   "prettier": {
@@ -61,11 +64,7 @@
     "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 4a77fb9..94dac6e 100644
--- a/readme.md
+++ b/readme.md
@@ -8,52 +8,117 @@
 [![Backers][backers-badge]][collective]
 [![Chat][chat-badge]][chat]
 
-**[mdast][]** utility to get the plain text content of a node.
+[mdast][] utility to get the text content of a node.
 
-## Install
+## Contents
+
+*   [What is this?](#what-is-this)
+*   [When should I use this?](#when-should-i-use-this)
+*   [Install](#install)
+*   [Use](#use)
+*   [API](#api)
+    *   [`toString(value[, options])`](#tostringvalue-options)
+    *   [`Options`](#options)
+*   [Types](#types)
+*   [Compatibility](#compatibility)
+*   [Security](#security)
+*   [Related](#related)
+*   [Contribute](#contribute)
+*   [License](#license)
+
+## What is this?
+
+This package is a tiny utility that gets the textual content of a node.
+
+## 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.
+This utility is useful when you have a node, say a heading, and want to get the
+text inside it.
 
-[npm][]:
+This package does not serialize markdown, that’s what
+[`mdast-util-to-markdown`][mdast-util-to-markdown] does.
+
+Similar packages, [`hast-util-to-string`][hast-util-to-string] and
+[`hast-util-to-text`][hast-util-to-text], do the same but on [hast][].
+
+## Install
+
+This package is [ESM only][esm].
+In Node.js (version 14.14+ and 16.0+), install with [npm][]:
 
 ```sh
 npm install mdast-util-to-string
 ```
 
+In Deno with [`esm.sh`][esmsh]:
+
+```js
+import {toString} from 'https://esm.sh/mdast-util-to-string@3'
+```
+
+In browsers with [`esm.sh`][esmsh]:
+
+```html
+<script type="module">
+  import {toString} from 'https://esm.sh/mdast-util-to-string@3?bundle'
+</script>
+```
+
 ## Use
 
 ```js
-import unified from 'unified'
-import remarkParse from 'remark-parse'
+import {unified} from 'unified'
+import {fromMarkdown} from 'mdast-util-from-markdown'
 import {toString} from 'mdast-util-to-string'
 
-var tree = unified()
-  .use(remarkParse)
-  .parse('Some _emphasis_, **importance**, and `code`.')
+const tree = fromMarkdown('Some _emphasis_, **importance**, and `code`.')
 
 console.log(toString(tree)) // => 'Some emphasis, importance, and code.'
 ```
 
 ## API
 
-This package exports the following identifiers: `toString`.
+This package exports the identifier [`toString`][api-tostring].
 There is no default export.
 
-### `toString(node[, options])`
+### `toString(value[, options])`
+
+Get the text content of a node or list of nodes.
+
+Prefers the node’s plain-text fields, otherwise serializes its children,
+and if the given value is an array, serialize the nodes in it.
+
+###### Parameters
 
-Get the text content of a [node][] or list of nodes.
+*   `value` (`unknown`)
+    — thing to serialize, typically [`Node`][node]
+*   `options` ([`Options`][api-options], optional)
+    — configuration
 
-The algorithm checks `value` of `node` and then `alt`.
-If no value is found, the algorithm checks the children of `node` and joins them
-(without spaces or newlines).
+###### Returns
 
-> This is not a markdown to plain-text library.
-> Use [`strip-markdown`][strip-markdown] for that.
+Serialized `value` (`string`).
 
-###### `options.includeImageAlt`
+### `Options`
 
-Whether to use `alt` (`boolean`, default: `true`)
+Configuration (TypeScript type).
+
+###### Fields
+
+*   `includeImageAlt` (`boolean`, default: `true`)
+    — whether to use `alt` for `image`s
+
+## Types
+
+This package is fully typed with [TypeScript][].
+It exports the additional type [`Options`][api-options].
+
+## Compatibility
+
+Projects maintained by the unified collective are compatible with all maintained
+versions of Node.js.
+As of now, that is Node.js 14.14+ and 16.0+.
+Our projects sometimes work with older versions, but this is not guaranteed.
 
 ## Security
 
@@ -63,19 +128,15 @@ attacks.
 
 ## Related
 
-*   [`nlcst-to-string`](https://github.com/syntax-tree/nlcst-to-string)
-    — Get text content in nlcst
-*   [`hast-util-to-string`](https://github.com/wooorm/rehype-minify/tree/HEAD/packages/hast-util-to-string)
-    — Get text content in hast
+*   [`hast-util-to-string`](https://github.com/wooorm/rehype-minify/tree/main/packages/hast-util-to-string)
+    — get text content in hast
 *   [`hast-util-to-text`](https://github.com/syntax-tree/hast-util-to-text)
-    — Get text content in hast according to the `innerText` algorithm
-*   [`hast-util-from-string`](https://github.com/wooorm/rehype-minify/tree/HEAD/packages/hast-util-from-string)
-    — Set text content in hast
+    — get text content in hast according to the `innerText` algorithm
 
 ## 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].
@@ -116,22 +177,38 @@ 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
+
+[coc]: https://github.com/syntax-tree/.github/blob/main/code-of-conduct.md
 
 [mdast]: https://github.com/syntax-tree/mdast
 
-[node]: https://github.com/syntax-tree/mdast#nodes
+[mdast-util-to-markdown]: https://github.com/syntax-tree/mdast-util-to-markdown
+
+[hast]: https://github.com/syntax-tree/hast
+
+[hast-util-to-string]: https://github.com/rehypejs/rehype-minify/tree/main/packages/hast-util-to-string
 
-[strip-markdown]: https://github.com/remarkjs/strip-markdown
+[hast-util-to-text]: https://github.com/syntax-tree/hast-util-to-text
+
+[node]: https://github.com/syntax-tree/mdast#nodes
 
 [xss]: https://en.wikipedia.org/wiki/Cross-site_scripting
 
-[hast]: https://github.com/syntax-tree/hast
+[api-tostring]: #tostringvalue-options
+
+[api-options]: #options
diff --git a/test.js b/test.js
index 3a4c6a3..1096c35 100644
--- a/test.js
+++ b/test.js
@@ -1,13 +1,26 @@
-import test from 'tape'
+import assert from 'node:assert/strict'
+import test from 'node:test'
 import {toString} from './index.js'
+import * as mod from './index.js'
 
-test('toString', function (t) {
-  t.equal(toString(), '', 'should not fail on a missing node')
-  t.equal(toString(null), '', 'should not fail on `null` missing node')
+test('toString', () => {
+  assert.deepEqual(
+    Object.keys(mod).sort(),
+    ['toString'],
+    'should expose the public api'
+  )
 
-  t.equal(toString({value: 'foo'}), 'foo', 'should not fail on nodes w/o type')
+  // @ts-expect-error: runtime.
+  assert.equal(toString(), '', 'should not fail on a missing node')
+  assert.equal(toString(null), '', 'should not fail on `null` missing node')
 
-  t.equal(
+  assert.equal(
+    toString({value: 'foo'}),
+    'foo',
+    'should not fail on nodes w/o type'
+  )
+
+  assert.equal(
     toString({
       value: 'foo',
       alt: 'bar',
@@ -18,37 +31,35 @@ test('toString', function (t) {
     'should prefer `value` over all others'
   )
 
-  t.equal(
+  assert.equal(
     toString({alt: 'bar', title: 'baz', children: [{value: 'qux'}]}),
     'bar',
     'should prefer `alt` over all others'
   )
 
-  t.equal(
+  assert.equal(
     toString({title: 'baz', children: [{value: 'qux'}]}),
     'qux',
     'should *not* prefer `title` over all others'
   )
 
-  t.equal(
+  assert.equal(
     toString({alt: 'bar'}, {includeImageAlt: false}),
     '',
     'should *not* include `alt` w/ `includeImageAlt: false`'
   )
 
-  t.equal(
+  assert.equal(
     toString({children: [{value: 'foo'}, {alt: 'bar'}, {title: 'baz'}]}),
     'foobar',
     'should serialize children'
   )
 
-  t.equal(
+  assert.equal(
     toString([{value: 'foo'}, {alt: 'bar'}, {title: 'baz'}]),
     'foobar',
     'should serialize a list of nodes'
   )
 
-  t.equal(toString({}), '', 'should produce an empty string otherwise')
-
-  t.end()
+  assert.equal(toString({}), '', 'should produce an empty string otherwise')
 })
diff --git a/tsconfig.json b/tsconfig.json
index be08abe..ebe8889 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,15 +1,17 @@
 {
-  "include": ["*.js"],
+  "include": ["**/*.js"],
+  "exclude": ["coverage/", "node_modules/"],
   "compilerOptions": {
-    "target": "ES2020",
-    "lib": ["ES2020"],
-    "module": "ES2020",
-    "moduleResolution": "node",
-    "allowJs": true,
     "checkJs": true,
     "declaration": true,
     "emitDeclarationOnly": true,
-    "allowSyntheticDefaultImports": true,
-    "skipLibCheck": true
+    "exactOptionalPropertyTypes": true,
+    "forceConsistentCasingInFileNames": true,
+    "lib": ["es2020"],
+    "module": "node16",
+    "newLine": "lf",
+    "skipLibCheck": true,
+    "strict": true,
+    "target": "es2020"
   }
 }