diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 441975c..346585c 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -10,10 +10,11 @@ jobs:
       fail-fast: false
       matrix:
         node-version:
-          - 16
+          - 20
+          - 18
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
         with:
           node-version: ${{ matrix.node-version }}
       - run: npm install
diff --git a/index.d.ts b/index.d.ts
index 3b3dcc0..6ae07ee 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -1,14 +1,14 @@
 import {
 	Duplex as DuplexStream,
-	DuplexOptions as DuplexStreamOption,
+	type DuplexOptions as DuplexStreamOption,
 } from 'node:stream';
 
-export interface Options extends Readonly<DuplexStreamOption> {
+export type Options = {
 	/**
 	The number of bytes to buffer.
 	*/
 	readonly chunkSize: number;
-}
+} & Readonly<DuplexStreamOption>;
 
 export type StopSymbol = typeof FirstChunkStream.stop;
 
@@ -44,11 +44,12 @@ export default class FirstChunkStream extends DuplexStream {
 	import fs from 'node:fs';
 	import getStream from 'get-stream';
 	import FirstChunkStream from 'first-chunk-stream';
+	import {uint8ArrayToString} from 'uint8array-extras';
 
 	// unicorn.txt => unicorn rainbow
 	const stream = fs.createReadStream('unicorn.txt')
 		.pipe(new FirstChunkStream({chunkSize: 7}, async (chunk, encoding) => {
-			return chunk.toString(encoding).toUpperCase();
+			return uint8ArrayToString(chunk).toUpperCase();
 		}));
 
 	const data = await getStream(stream);
diff --git a/index.js b/index.js
index b90b3a6..382b9a7 100644
--- a/index.js
+++ b/index.js
@@ -69,7 +69,7 @@ export default class FirstChunkStream extends DuplexStream {
 			} else {
 				state.chunks.push(chunk.slice(0, options.chunkSize - state.size));
 				chunk = chunk.slice(options.chunkSize - state.size);
-				state.size += state.chunks[state.chunks.length - 1].length;
+				state.size += state.chunks.at(-1).length;
 
 				processCallback(concatUint8Arrays(state.chunks, state.size), state.encoding, () => {
 					if (chunk.length === 0) {
diff --git a/index.test-d.ts b/index.test-d.ts
index eb53ce1..710a68e 100644
--- a/index.test-d.ts
+++ b/index.test-d.ts
@@ -1,5 +1,5 @@
 import fs from 'node:fs';
-import {Duplex as DuplexStream} from 'node:stream';
+import {type Duplex as DuplexStream} from 'node:stream';
 import {expectType, expectError} from 'tsd';
 import {stringToUint8Array} from 'uint8array-extras';
 import FirstChunkStream from './index.js';
@@ -14,7 +14,7 @@ const firstChunkStream = new FirstChunkStream({chunkSize: 7}, async (chunk, enco
 expectType<FirstChunkStream>(firstChunkStream);
 expectType<DuplexStream>(firstChunkStream);
 
-fs.createReadStream('unicorn.txt').pipe(firstChunkStream); // eslint-disable-line @typescript-eslint/no-unsafe-member-access
+fs.createReadStream('unicorn.txt').pipe(firstChunkStream);
 
 expectType<FirstChunkStream>(new FirstChunkStream({chunkSize: 7}, async () => FirstChunkStream.stop));
 expectType<FirstChunkStream>(new FirstChunkStream({chunkSize: 7}, async () => ''));
diff --git a/package.json b/package.json
index 08c0203..45b69f1 100644
--- a/package.json
+++ b/package.json
@@ -13,7 +13,7 @@
 	"type": "module",
 	"exports": "./index.js",
 	"engines": {
-		"node": "^12.20.0 || ^14.13.1 || >=16.0.0"
+		"node": ">=18"
 	},
 	"scripts": {
 		"test": "xo && nyc ava && tsd"
@@ -37,11 +37,16 @@
 		"uint8array-extras": "^0.5.0"
 	},
 	"devDependencies": {
-		"@types/node": "^16.6.1",
+		"@types/node": "^20.8.10",
 		"ava": "^3.15.0",
 		"nyc": "^15.1.0",
 		"streamtest": "^2.0.0",
-		"tsd": "^0.17.0",
-		"xo": "^0.44.0"
+		"tsd": "^0.29.0",
+		"xo": "^0.56.0"
+	},
+	"xo": {
+		"rules": {
+			"ava/no-unknown-modifiers": "off"
+		}
 	}
 }
diff --git a/readme.md b/readme.md
index 6180b5a..e79bd37 100644
--- a/readme.md
+++ b/readme.md
@@ -4,8 +4,8 @@
 
 ## Install
 
-```
-$ npm install first-chunk-stream
+```sh
+npm install first-chunk-stream
 ```
 
 ## Usage
@@ -14,11 +14,12 @@ $ npm install first-chunk-stream
 import fs from 'node:fs';
 import getStream from 'get-stream';
 import FirstChunkStream from 'first-chunk-stream';
+import {uint8ArrayToString} from 'uint8array-extras';
 
 // unicorn.txt => unicorn rainbow
 const stream = fs.createReadStream('unicorn.txt')
 	.pipe(new FirstChunkStream({chunkSize: 7}, async (chunk, encoding) => {
-		return chunk.toString(encoding).toUpperCase();
+		return uint8ArrayToString(chunk).toUpperCase();
 	}));
 
 const data = await getStream(stream);
diff --git a/test.js b/test.js
index 65a32b0..617acd1 100644
--- a/test.js
+++ b/test.js
@@ -201,7 +201,7 @@ for (const version of streamtest.versions) {
 			t.plan(2);
 
 			streamtest[version]
-				.fromChunks(content.split(''))
+				.fromChunks([...content])
 				.pipe(
 					new FirstChunkStream(
 						{chunkSize: 7},
@@ -230,7 +230,7 @@ for (const version of streamtest.versions) {
 		t => {
 			t.plan(2);
 
-			const inputStream = streamtest[version].fromChunks(content.split(''));
+			const inputStream = streamtest[version].fromChunks([...content]);
 
 			const firstChunkStream = inputStream.pipe(
 				new FirstChunkStream(
@@ -410,7 +410,7 @@ for (const version of streamtest.versions) {
 			t.plan(2);
 
 			streamtest[version]
-				.fromChunks(content.split(''))
+				.fromChunks([...content])
 				.pipe(
 					new FirstChunkStream(
 						{chunkSize: 7},