diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a6ea1d4..80cf038 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -24,4 +24,6 @@ jobs:
 
       - run: npm ci
 
+      - run: npm run typecheck
+
       - run: npm test
diff --git a/bplistParser.d.ts b/bplistParser.d.ts
deleted file mode 100644
index 28b845d..0000000
--- a/bplistParser.d.ts
+++ /dev/null
@@ -1,26 +0,0 @@
-export type CallbackFunction<T = any> = (error: Error | null, result: [T]) => void;
-
-/** Maximum size, in bytes, of an object the parser will allocate. Read-only; use {@link setMaxObjectSize}. */
-export declare const maxObjectSize: number;
-
-/** Maximum number of objects the parser will read from a plist. Read-only; use {@link setMaxObjectCount}. */
-export declare const maxObjectCount: number;
-
-export declare function setMaxObjectSize(value: number): void;
-
-export declare function setMaxObjectCount(value: number): void;
-
-/** Wrapper for a CoreFoundation keyed-archiver UID value. */
-export declare class UID {
-  constructor(id: number);
-  UID: number;
-}
-
-export declare function parseFile<T = any>(
-  fileNameOrBuffer: string | Buffer,
-  callback?: CallbackFunction<T>
-): Promise<[T]>;
-
-export declare function parseFileSync<T = any>(fileNameOrBuffer: string | Buffer): [T];
-
-export declare function parseBuffer<T = any>(buffer: string | Buffer): [T];
diff --git a/bplistParser.js b/bplistParser.ts
similarity index 84%
rename from bplistParser.js
rename to bplistParser.ts
index ee92edb..38fcbe8 100644
--- a/bplistParser.js
+++ b/bplistParser.ts
@@ -1,7 +1,5 @@
 /* eslint-disable no-console */
 
-'use strict';
-
 // adapted from https://github.com/3breadt/dd-plist
 
 import fs from 'node:fs';
@@ -13,11 +11,11 @@ export let maxObjectCount = 32768;
 // Exported bindings are read-only to consumers (an ESM import binding cannot be
 // assigned, and the CommonJS build exposes exports as getters), so these knobs
 // are tuned through setters rather than by assigning to the exports.
-export function setMaxObjectSize(value) {
+export function setMaxObjectSize(value: number): void {
   maxObjectSize = value;
 }
 
-export function setMaxObjectCount(value) {
+export function setMaxObjectCount(value: number): void {
   maxObjectCount = value;
 }
 
@@ -26,21 +24,30 @@ export function setMaxObjectCount(value) {
 // So we just hardcode the correct value.
 const EPOCH = 978307200000;
 
-// UID object definition
-export const UID = function(id) {
-  this.UID = id;
-};
+/** Wrapper for a CoreFoundation keyed-archiver UID value. */
+export class UID {
+  UID: number;
+
+  constructor(id: number) {
+    this.UID = id;
+  }
+}
+
+export type CallbackFunction<T = any> = (error: Error | null, result?: [T]) => void;
 
-export const parseFile = function (fileNameOrBuffer, callback) {
-  return new Promise(function (resolve, reject) {
-    function tryParseBuffer(buffer) {
-      let err = null;
-      let result;
+export function parseFile<T = any>(
+  fileNameOrBuffer: string | Buffer,
+  callback?: CallbackFunction<T>
+): Promise<[T]> {
+  return new Promise<[T]>(function (resolve, reject) {
+    function tryParseBuffer(buffer: Buffer) {
+      let err: Error | null = null;
+      let result: [T] | undefined;
       try {
-        result = parseBuffer(buffer);
+        result = parseBuffer<T>(buffer);
         resolve(result);
       } catch (ex) {
-        err = ex;
+        err = ex as Error;
         reject(err);
       } finally {
         if (callback) callback(err, result);
@@ -59,16 +66,14 @@ export const parseFile = function (fileNameOrBuffer, callback) {
       tryParseBuffer(data);
     });
   });
-};
+}
 
-export const parseFileSync = function (fileNameOrBuffer) {
-  if (!Buffer.isBuffer(fileNameOrBuffer)) {
-    fileNameOrBuffer = fs.readFileSync(fileNameOrBuffer);
-  }
-  return parseBuffer(fileNameOrBuffer);
-};
+export function parseFileSync<T = any>(fileNameOrBuffer: string | Buffer): [T] {
+  const buffer = Buffer.isBuffer(fileNameOrBuffer) ? fileNameOrBuffer : fs.readFileSync(fileNameOrBuffer);
+  return parseBuffer<T>(buffer);
+}
 
-export const parseBuffer = function (buffer) {
+export function parseBuffer<T = any>(buffer: Buffer): [T] {
   // check header
   const header = buffer.slice(0, 'bplist00'.length).toString('utf8');
   if (header !== 'bplist00') {
@@ -107,7 +112,7 @@ export const parseBuffer = function (buffer) {
   }
 
   // Handle offset table
-  const offsetTable = [];
+  const offsetTable: number[] = [];
 
   for (let i = 0; i < numObjects; i++) {
     const offsetBytes = buffer.slice(offsetTableOffset + i * offsetSize, offsetTableOffset + (i + 1) * offsetSize);
@@ -121,7 +126,7 @@ export const parseBuffer = function (buffer) {
   // For the format specification check
   // <a href="https://www.opensource.apple.com/source/CF/CF-635/CFBinaryPList.c">
   // Apple's binary property list parser implementation</a>.
-  function parseObject(tableOffset) {
+  function parseObject(tableOffset: number): any {
     const offset = offsetTable[tableOffset];
     const type = buffer[offset];
     const objType = (type & 0xF0) >> 4; //First  4 bits
@@ -151,7 +156,7 @@ export const parseBuffer = function (buffer) {
       throw new Error("Unhandled type 0x" + objType.toString(16));
     }
 
-    function parseSimple() {
+    function parseSimple(): any {
       //Simple
       switch (objInfo) {
       case 0x0: // null
@@ -167,7 +172,7 @@ export const parseBuffer = function (buffer) {
       }
     }
 
-    function parseInteger() {
+    function parseInteger(): number | bigint {
       const length = Math.pow(2, objInfo);
       if (length < maxObjectSize) {
         const data = buffer.slice(offset + 1, offset + 1 + length);
@@ -177,7 +182,7 @@ export const parseBuffer = function (buffer) {
 
     }
 
-    function parseUID() {
+    function parseUID(): UID {
       const length = objInfo + 1;
       if (length < maxObjectSize) {
         return new UID(readUInt(buffer.slice(offset + 1, offset + 1 + length)));
@@ -185,7 +190,7 @@ export const parseBuffer = function (buffer) {
       throw new Error("Too little heap space available! Wanted to read " + length + " bytes, but only " + maxObjectSize + " are available.");
     }
 
-    function parseReal() {
+    function parseReal(): number | undefined {
       const length = Math.pow(2, objInfo);
       if (length < maxObjectSize) {
         const realBuffer = buffer.slice(offset + 1, offset + 1 + length);
@@ -200,7 +205,7 @@ export const parseBuffer = function (buffer) {
       }
     }
 
-    function parseDate() {
+    function parseDate(): Date {
       if (objInfo != 0x3) {
         console.error("Unknown date type :" + objInfo + ". Parsing anyway...");
       }
@@ -208,7 +213,7 @@ export const parseBuffer = function (buffer) {
       return new Date(EPOCH + (1000 * dateBuffer.readDoubleBE(0)));
     }
 
-    function parseData() {
+    function parseData(): Buffer {
       let dataoffset = 1;
       let length = objInfo;
       if (objInfo == 0xF) {
@@ -232,9 +237,9 @@ export const parseBuffer = function (buffer) {
       throw new Error("Too little heap space available! Wanted to read " + length + " bytes, but only " + maxObjectSize + " are available.");
     }
 
-    function parsePlistString (isUtf16) {
-      isUtf16 = isUtf16 || 0;
-      let enc = "utf8";
+    function parsePlistString(isUtf16?: boolean): string {
+      const utf16Flag = isUtf16 || false;
+      let enc: BufferEncoding = "utf8";
       let length = objInfo;
       let stroffset = 1;
       if (objInfo == 0xF) {
@@ -253,10 +258,10 @@ export const parseBuffer = function (buffer) {
         }
       }
       // length is String length -> to get byte length multiply by 2, as 1 character takes 2 bytes in UTF-16
-      length *= (isUtf16 + 1);
+      length *= (utf16Flag ? 2 : 1);
       if (length < maxObjectSize) {
         let plistString = Buffer.from(buffer.slice(offset + stroffset, offset + stroffset + length));
-        if (isUtf16) {
+        if (utf16Flag) {
           plistString = swapBytes(plistString);
           enc = "ucs2";
         }
@@ -265,7 +270,7 @@ export const parseBuffer = function (buffer) {
       throw new Error("Too little heap space available! Wanted to read " + length + " bytes, but only " + maxObjectSize + " are available.");
     }
 
-    function parseArray() {
+    function parseArray(): any[] {
       let length = objInfo;
       let arrayoffset = 1;
       if (objInfo == 0xF) {
@@ -286,7 +291,7 @@ export const parseBuffer = function (buffer) {
       if (length * objectRefSize > maxObjectSize) {
         throw new Error("Too little heap space available!");
       }
-      const array = [];
+      const array: any[] = [];
       for (let i = 0; i < length; i++) {
         const objRef = readUInt(buffer.slice(offset + arrayoffset + i * objectRefSize, offset + arrayoffset + (i + 1) * objectRefSize));
         array[i] = parseObject(objRef);
@@ -294,7 +299,7 @@ export const parseBuffer = function (buffer) {
       return array;
     }
 
-    function parseDictionary() {
+    function parseDictionary(): Record<string, any> {
       let length = objInfo;
       let dictoffset = 1;
       if (objInfo == 0xF) {
@@ -318,7 +323,7 @@ export const parseBuffer = function (buffer) {
       if (debug) {
         console.log("Parsing dictionary #" + tableOffset);
       }
-      const dict = {};
+      const dict: Record<string, any> = {};
       for (let i = 0; i < length; i++) {
         const keyRef = readUInt(buffer.slice(offset + dictoffset + i * objectRefSize, offset + dictoffset + (i + 1) * objectRefSize));
         const valRef = readUInt(buffer.slice(offset + dictoffset + (length * objectRefSize) + i * objectRefSize, offset + dictoffset + (length * objectRefSize) + (i + 1) * objectRefSize));
@@ -334,9 +339,9 @@ export const parseBuffer = function (buffer) {
   }
 
   return [ parseObject(topObject) ];
-};
+}
 
-function readUInt(buffer, start) {
+function readUInt(buffer: Buffer, start?: number): number {
   start = start || 0;
 
   let l = 0;
@@ -346,7 +351,7 @@ function readUInt(buffer, start) {
   return l;
 }
 
-function readBigUInt(buffer) {
+function readBigUInt(buffer: Buffer): bigint {
   let value = 0n;
   for (const byte of buffer) {
     value = (value << 8n) | BigInt(byte);
@@ -354,14 +359,14 @@ function readBigUInt(buffer) {
   return value;
 }
 
-function simplifyInteger(value) {
+function simplifyInteger(value: bigint): number | bigint {
   if (value >= BigInt(Number.MIN_SAFE_INTEGER) && value <= BigInt(Number.MAX_SAFE_INTEGER)) {
     return Number(value);
   }
   return value;
 }
 
-function readInteger(buffer) {
+function readInteger(buffer: Buffer): number | bigint {
   let value = readBigUInt(buffer);
 
   if (buffer.length === 8 && (buffer[0] & 0x80)) {
@@ -372,12 +377,12 @@ function readInteger(buffer) {
 }
 
 // we're just going to toss the high order bits because javascript doesn't have 64-bit ints
-function readUInt64BE(buffer, start) {
+function readUInt64BE(buffer: Buffer, start: number): number {
   const data = buffer.slice(start, start + 8);
   return readUInt(data, 0);
 }
 
-function swapBytes(buffer) {
+function swapBytes<T extends Buffer>(buffer: T): T {
   const len = buffer.length;
   for (let i = 0; i < len; i += 2) {
     const a = buffer[i];
diff --git a/build.js b/build.js
index a5ff5e0..075cbb3 100644
--- a/build.js
+++ b/build.js
@@ -1,7 +1,8 @@
 import { build } from 'esbuild';
-import { copyFile, mkdir, readFile, writeFile } from 'fs/promises';
+import { execFileSync } from 'node:child_process';
+import { mkdir, readFile, rm, writeFile } from 'fs/promises';
 
-const entry = 'bplistParser.js';
+const entry = 'bplistParser.ts';
 const outdir = 'dist';
 
 await mkdir(outdir, { recursive: true });
@@ -20,10 +21,15 @@ await Promise.all([
   build({ ...common, format: 'cjs', outfile: `${outdir}/index.cjs` }),
 ]);
 
-// Ship the same declarations under both extensions so `import` and `require`
-// consumers each resolve types under their own resolution mode.
-const types = await readFile('bplistParser.d.ts', 'utf8');
-await writeFile(`${outdir}/index.d.ts`, types);
-await writeFile(`${outdir}/index.d.cts`, types);
+// tsc emits the declaration for the entry file into dist/types; ship the same
+// declarations under both extensions so `import` and `require` consumers each
+// resolve types under their own resolution mode.
+execFileSync('npx', ['tsc', '-p', 'tsconfig.build.json'], { stdio: 'inherit' });
+const types = await readFile(`${outdir}/types/bplistParser.d.ts`, 'utf8');
+await Promise.all([
+  writeFile(`${outdir}/index.d.ts`, types),
+  writeFile(`${outdir}/index.d.cts`, types),
+]);
+await rm(`${outdir}/types`, { recursive: true, force: true });
 
 console.log('built', outdir);
diff --git a/eslint.config.js b/eslint.config.js
index 54ccc05..4d4acd5 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -1,11 +1,22 @@
 import js from '@eslint/js';
+import tseslint from 'typescript-eslint';
 import globals from 'globals';
 
-export default [
+export default tseslint.config(
   {
     ignores: ['dist/**', 'node_modules/**'],
   },
   js.configs.recommended,
+  {
+    files: ['**/*.ts'],
+    extends: [...tseslint.configs.recommended],
+    rules: {
+      // Parsing/creating plists is inherently dynamic (arbitrary nested
+      // dicts/arrays of unknown shape); `any` is the honest type here, not a
+      // shortcut.
+      '@typescript-eslint/no-explicit-any': 'off',
+    },
+  },
   {
     languageOptions: {
       ecmaVersion: 2022,
@@ -48,4 +59,4 @@ export default [
       },
     },
   },
-];
+);
diff --git a/package-lock.json b/package-lock.json
index 2ac6572..964a564 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,18 +1,21 @@
 {
   "name": "bplist-parser",
-  "version": "0.4.0",
+  "version": "0.5.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "bplist-parser",
-      "version": "0.4.0",
+      "version": "0.5.0",
       "license": "MIT",
       "devDependencies": {
         "@eslint/js": "10.0.x",
+        "@types/node": "26.4.x",
         "esbuild": "0.28.x",
         "eslint": "10.10.x",
         "globals": "17.12.x",
+        "typescript": "6.0.x",
+        "typescript-eslint": "8.69.x",
         "vitest": "5.0.x"
       },
       "engines": {
@@ -1077,6 +1080,246 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/@types/node": {
+      "version": "26.4.1",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-26.4.1.tgz",
+      "integrity": "sha512-k97ENvZWtvA6yqz5/FS6a7duDgOPEeOQOc2iKS/nY6mX6qJUKtLnWzQS+Xj6tXweyj6ZcTAK2Qecetnvi9nCLA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "undici-types": "~8.3.0"
+      }
+    },
+    "node_modules/@typescript-eslint/eslint-plugin": {
+      "version": "8.69.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-8.69.0.tgz",
+      "integrity": "sha512-t5jQTKPIgVW1PE6dR6H6Qz5gm8zjMlX5/2gRaOGd9eO6V7J+tQc6iWKukEe7dY8u9HyYasQ0yfF0/FSSTEO2gA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@eslint-community/regexpp": "^4.12.2",
+        "@typescript-eslint/scope-manager": "8.69.0",
+        "@typescript-eslint/type-utils": "8.69.0",
+        "@typescript-eslint/utils": "8.69.0",
+        "@typescript-eslint/visitor-keys": "8.69.0",
+        "ignore": "^7.0.5",
+        "natural-compare": "^1.4.0",
+        "ts-api-utils": "^2.5.0"
+      },
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/typescript-eslint"
+      },
+      "peerDependencies": {
+        "@typescript-eslint/parser": "^8.69.0",
+        "eslint": "^8.57.0 || ^9.0.0 || ^10.0.0",
+        "typescript": ">=4.8.4 <6.1.0"
+      }
+    },
+    "node_modules/@typescript-eslint/eslint-plugin/node_modules/ignore": {
+      "version": "7.0.8",
+      "resolved": "https://registry.npmjs.org/ignore/-/ignore-7.0.8.tgz",
+      "integrity": "sha512-YYNsSlXBjMk92SKnkwvB5LOVSa6OznlFUGcsvrFgNJbJCd0M1XKeFVRc8ZByeCqz32FivYNHJVooLmdqrmvp/Q==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">= 4"
+      }
+    },
+    "node_modules/@typescript-eslint/parser": {
+      "version": "8.69.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/parser/-/parser-8.69.0.tgz",
+      "integrity": "sha512-l4b0DhWioGg6Gt2ebGlvfkFMOjRsauxtsnDRwUSRX1qHq3HdTfQHV8wW9zEXeciai6HfeaKOedQn2Zoofx3WBw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@typescript-eslint/scope-manager": "8.69.0",
+        "@typescript-eslint/types": "8.69.0",
+        "@typescript-eslint/typescript-estree": "8.69.0",
+        "@typescript-eslint/visitor-keys": "8.69.0",
+        "debug": "^4.4.3"
+      },
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/typescript-eslint"
+      },
+      "peerDependencies": {
+        "eslint": "^8.57.0 || ^9.0.0 || ^10.0.0",
+        "typescript": ">=4.8.4 <6.1.0"
+      }
+    },
+    "node_modules/@typescript-eslint/project-service": {
+      "version": "8.69.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/project-service/-/project-service-8.69.0.tgz",
+      "integrity": "sha512-yi4obFrHMmnsesWehHbkg9zMA7Jt8cXT+mKM08G999pH1yT6nqgsHx7MYm0uY1wAj8CqiBXYRJ7WAT0QdQHQXg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@typescript-eslint/tsconfig-utils": "^8.69.0",
+        "@typescript-eslint/types": "^8.69.0",
+        "debug": "^4.4.3"
+      },
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/typescript-eslint"
+      },
+      "peerDependencies": {
+        "typescript": ">=4.8.4 <6.1.0"
+      }
+    },
+    "node_modules/@typescript-eslint/scope-manager": {
+      "version": "8.69.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/scope-manager/-/scope-manager-8.69.0.tgz",
+      "integrity": "sha512-ewfspqWvSxKSOaplqAUNbaSFO0eB6w1EtQ+esfYFRm3614Ty4uNtExkcbgd6nWsXphbqKyf9ZYdbZdv2xEoWEQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@typescript-eslint/types": "8.69.0",
+        "@typescript-eslint/visitor-keys": "8.69.0"
+      },
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/typescript-eslint"
+      }
+    },
+    "node_modules/@typescript-eslint/tsconfig-utils": {
+      "version": "8.69.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/tsconfig-utils/-/tsconfig-utils-8.69.0.tgz",
+      "integrity": "sha512-xNqK7YTDZsLniQMV/4rpFR8Z5JlqeRvVjuG1YgF/mdPVH84HSD19L8CczMA0qg2RfwEV231GHH3VnToJDo4MfQ==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/typescript-eslint"
+      },
+      "peerDependencies": {
+        "typescript": ">=4.8.4 <6.1.0"
+      }
+    },
+    "node_modules/@typescript-eslint/type-utils": {
+      "version": "8.69.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/type-utils/-/type-utils-8.69.0.tgz",
+      "integrity": "sha512-ZfoJAVg3JZndQEpEl9petVlxau3lRuElc4HRMuAlLCf8to04/iHz692RUSNmXKDjEuJmIL+KZ2/BsOcBc16dsA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@typescript-eslint/types": "8.69.0",
+        "@typescript-eslint/typescript-estree": "8.69.0",
+        "@typescript-eslint/utils": "8.69.0",
+        "debug": "^4.4.3",
+        "ts-api-utils": "^2.5.0"
+      },
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/typescript-eslint"
+      },
+      "peerDependencies": {
+        "eslint": "^8.57.0 || ^9.0.0 || ^10.0.0",
+        "typescript": ">=4.8.4 <6.1.0"
+      }
+    },
+    "node_modules/@typescript-eslint/types": {
+      "version": "8.69.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/types/-/types-8.69.0.tgz",
+      "integrity": "sha512-K3VrubUPhlo9VDBS6QdI8YB5j7ClpqLRdefcz6PFrhnwicehBweqQ9Evhl4l+FYz0HdDmMqIiSX0aldGRYtDCA==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/typescript-eslint"
+      }
+    },
+    "node_modules/@typescript-eslint/typescript-estree": {
+      "version": "8.69.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/typescript-estree/-/typescript-estree-8.69.0.tgz",
+      "integrity": "sha512-AdFkgqck3Vudb/kWnxlyafU/4aBhHrbQ9locP2N4psXTy5mOBg0SHJumnLvx7r6g1gV4DKvUFwV2nJZBoqOD8w==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@typescript-eslint/project-service": "8.69.0",
+        "@typescript-eslint/tsconfig-utils": "8.69.0",
+        "@typescript-eslint/types": "8.69.0",
+        "@typescript-eslint/visitor-keys": "8.69.0",
+        "debug": "^4.4.3",
+        "minimatch": "^10.2.2",
+        "semver": "^7.7.3",
+        "tinyglobby": "^0.2.15",
+        "ts-api-utils": "^2.5.0"
+      },
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/typescript-eslint"
+      },
+      "peerDependencies": {
+        "typescript": ">=4.8.4 <6.1.0"
+      }
+    },
+    "node_modules/@typescript-eslint/utils": {
+      "version": "8.69.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/utils/-/utils-8.69.0.tgz",
+      "integrity": "sha512-tUbx60BBqQa31kXF5MCsOOLL5E/WzUuxIn7YpAvq+eaUlqvk8/NXnXMBNAdLCr0icjkzem7iUA5QqWHe/hJ1aw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@eslint-community/eslint-utils": "^4.9.1",
+        "@typescript-eslint/scope-manager": "8.69.0",
+        "@typescript-eslint/types": "8.69.0",
+        "@typescript-eslint/typescript-estree": "8.69.0"
+      },
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/typescript-eslint"
+      },
+      "peerDependencies": {
+        "eslint": "^8.57.0 || ^9.0.0 || ^10.0.0",
+        "typescript": ">=4.8.4 <6.1.0"
+      }
+    },
+    "node_modules/@typescript-eslint/visitor-keys": {
+      "version": "8.69.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/visitor-keys/-/visitor-keys-8.69.0.tgz",
+      "integrity": "sha512-+rmdgPA+EXkNgKYvHvFfhrs35utXbwaC5PGpDquSXcoXQDKUA5UjV0LmTucG/4JXkM31BTu4TilHtrN8IVBe8w==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@typescript-eslint/types": "8.69.0",
+        "eslint-visitor-keys": "^5.0.0"
+      },
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/typescript-eslint"
+      }
+    },
     "node_modules/@vitest/mocker": {
       "version": "5.0.0",
       "resolved": "https://registry.npmjs.org/@vitest/mocker/-/mocker-5.0.0.tgz",
@@ -2306,6 +2549,19 @@
         "@rolldown/binding-win32-x64-msvc": "1.2.7"
       }
     },
+    "node_modules/semver": {
+      "version": "7.8.5",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.8.5.tgz",
+      "integrity": "sha512-Y7/KDsb8LjooZpwaqGyulO6DQlksgCncchHGk+sZIY4SBvUocMBEFH5Ur1fI4dV+Jvl0w6cjvucaIi40puRioA==",
+      "dev": true,
+      "license": "ISC",
+      "bin": {
+        "semver": "bin/semver.js"
+      },
+      "engines": {
+        "node": ">=10"
+      }
+    },
     "node_modules/shebang-command": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/shebang-command/-/shebang-command-2.0.0.tgz",
@@ -2398,6 +2654,19 @@
         "url": "https://github.com/sponsors/SuperchupuDev"
       }
     },
+    "node_modules/ts-api-utils": {
+      "version": "2.5.0",
+      "resolved": "https://registry.npmjs.org/ts-api-utils/-/ts-api-utils-2.5.0.tgz",
+      "integrity": "sha512-OJ/ibxhPlqrMM0UiNHJ/0CKQkoKF243/AEmplt3qpRgkW8VG7IfOS41h7V8TjITqdByHzrjcS/2si+y4lIh8NA==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=18.12"
+      },
+      "peerDependencies": {
+        "typescript": ">=4.8.4"
+      }
+    },
     "node_modules/type-check": {
       "version": "0.4.0",
       "resolved": "https://registry.npmjs.org/type-check/-/type-check-0.4.0.tgz",
@@ -2411,6 +2680,51 @@
         "node": ">= 0.8.0"
       }
     },
+    "node_modules/typescript": {
+      "version": "6.0.3",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-6.0.3.tgz",
+      "integrity": "sha512-y2TvuxSZPDyQakkFRPZHKFm+KKVqIisdg9/CZwm9ftvKXLP8NRWj38/ODjNbr43SsoXqNuAisEf1GdCxqWcdBw==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "bin": {
+        "tsc": "bin/tsc",
+        "tsserver": "bin/tsserver"
+      },
+      "engines": {
+        "node": ">=14.17"
+      }
+    },
+    "node_modules/typescript-eslint": {
+      "version": "8.69.0",
+      "resolved": "https://registry.npmjs.org/typescript-eslint/-/typescript-eslint-8.69.0.tgz",
+      "integrity": "sha512-B3MltX0VqjUBNEe3b3sSuiRbfa6XrfHFtBiPamjT5AsW/dfq+y+bc0wyuS9DxAS1LyzCxRp2+rxzpLUvqM2BvA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@typescript-eslint/eslint-plugin": "8.69.0",
+        "@typescript-eslint/parser": "8.69.0",
+        "@typescript-eslint/typescript-estree": "8.69.0",
+        "@typescript-eslint/utils": "8.69.0"
+      },
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/typescript-eslint"
+      },
+      "peerDependencies": {
+        "eslint": "^8.57.0 || ^9.0.0 || ^10.0.0",
+        "typescript": ">=4.8.4 <6.1.0"
+      }
+    },
+    "node_modules/undici-types": {
+      "version": "8.3.0",
+      "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-8.3.0.tgz",
+      "integrity": "sha512-j375ScV60dom+YkPFIfTLcOiPxkN/buHz5GobjLhixFuANaNs3C9l4GmrWqejgXWJ7BbJcFYpTEUkS1Ge8bpZQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/uri-js": {
       "version": "4.4.1",
       "resolved": "https://registry.npmjs.org/uri-js/-/uri-js-4.4.1.tgz",
diff --git a/package.json b/package.json
index 1ff7e4f..e8fa9ee 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "bplist-parser",
-  "version": "0.4.0",
+  "version": "0.5.0",
   "description": "Binary plist parser.",
   "type": "module",
   "main": "./dist/index.cjs",
@@ -25,9 +25,10 @@
   "scripts": {
     "build": "node build.js",
     "lint": "eslint .",
+    "typecheck": "tsc --noEmit",
     "test": "vitest run",
     "smoke": "npm run build && node smoke.cjs",
-    "prepublishOnly": "npm run build"
+    "prepublishOnly": "npm run typecheck && npm run build"
   },
   "keywords": [
     "bplist",
@@ -41,9 +42,12 @@
   "license": "MIT",
   "devDependencies": {
     "@eslint/js": "10.0.x",
+    "@types/node": "26.4.x",
     "esbuild": "0.28.x",
     "eslint": "10.10.x",
     "globals": "17.12.x",
+    "typescript": "6.0.x",
+    "typescript-eslint": "8.69.x",
     "vitest": "5.0.x"
   },
   "homepage": "https://github.com/nearinfinity/node-bplist-parser",
diff --git a/test/parse.test.js b/test/parse.test.ts
similarity index 86%
rename from test/parse.test.js
rename to test/parse.test.ts
index c86f312..80e2494 100644
--- a/test/parse.test.js
+++ b/test/parse.test.ts
@@ -14,7 +14,7 @@ describe('bplist-parser', function () {
 
     const [dict] = await bplist.parseFile(file);
     const endTime = new Date();
-    console.log('Parsed "' + file + '" in ' + (endTime - startTime1) + 'ms');
+    console.log('Parsed "' + file + '" in ' + (endTime.getTime() - startTime1.getTime()) + 'ms');
     assert.equal(dict['Application Version'], "9.0.3");
     assert.equal(dict['Library Persistent ID'], "6F81D37F95101437");
     assert.deepEqual(dict, bplist.parseFileSync(file)[0]);
@@ -26,7 +26,7 @@ describe('bplist-parser', function () {
 
     const [dict] = await bplist.parseFile(file);
     const endTime = new Date();
-    console.log('Parsed "' + file + '" in ' + (endTime - startTime) + 'ms');
+    console.log('Parsed "' + file + '" in ' + (endTime.getTime() - startTime.getTime()) + 'ms');
 
     assert.equal(dict['CFBundleIdentifier'], 'com.apple.dictionary.MySample');
     assert.deepEqual(dict, bplist.parseFileSync(file)[0]);
@@ -38,7 +38,7 @@ describe('bplist-parser', function () {
 
     const [dict] = await bplist.parseFile(file);
     const endTime = new Date();
-    console.log('Parsed "' + file + '" in ' + (endTime - startTime) + 'ms');
+    console.log('Parsed "' + file + '" in ' + (endTime.getTime() - startTime.getTime()) + 'ms');
 
     assert.equal(dict['PopupMenu'][2]['Key'], "\n        #import <Cocoa/Cocoa.h>\n\n#import <MacRuby/MacRuby.h>\n\nint main(int argc, char *argv[])\n{\n  return macruby_main(\"rb_main.rb\", argc, argv);\n}\n");
     assert.deepEqual(dict, bplist.parseFileSync(file)[0]);
@@ -50,7 +50,7 @@ describe('bplist-parser', function () {
 
     const [dict] = await bplist.parseFile(file);
     const endTime = new Date();
-    console.log('Parsed "' + file + '" in ' + (endTime - startTime) + 'ms');
+    console.log('Parsed "' + file + '" in ' + (endTime.getTime() - startTime.getTime()) + 'ms');
 
     assert.equal(dict['duration'], 5555.0495000000001);
     assert.equal(dict['position'], 4.6269989039999997);
@@ -63,7 +63,7 @@ describe('bplist-parser', function () {
 
     const [dict] = await bplist.parseFile(file);
     const endTime = new Date();
-    console.log('Parsed "' + file + '" in ' + (endTime - startTime) + 'ms');
+    console.log('Parsed "' + file + '" in ' + (endTime.getTime() - startTime.getTime()) + 'ms');
 
     assert.equal(dict['CFBundleName'], 'sellStuff');
     assert.equal(dict['CFBundleShortVersionString'], '2.6.1');
@@ -77,7 +77,7 @@ describe('bplist-parser', function () {
 
     const [dict] = await bplist.parseFile(file);
     const endTime = new Date();
-    console.log('Parsed "' + file + '" in ' + (endTime - startTime) + 'ms');
+    console.log('Parsed "' + file + '" in ' + (endTime.getTime() - startTime.getTime()) + 'ms');
 
     assert.equal(dict['CFBundleName'], '天翼阅读');
     assert.equal(dict['CFBundleDisplayName'], '天翼阅读');
@@ -90,7 +90,7 @@ describe('bplist-parser', function () {
 
     const [dict] = await bplist.parseFile(file);
     const endTime = new Date();
-    console.log('Parsed "' + file + '" in ' + (endTime - startTime) + 'ms');
+    console.log('Parsed "' + file + '" in ' + (endTime.getTime() - startTime.getTime()) + 'ms');
 
     assert.deepEqual(dict['$objects'][1]['NS.keys'], [{UID:2}, {UID:3}, {UID:4}]);
     assert.deepEqual(dict['$objects'][1]['NS.objects'], [{UID: 5}, {UID:6}, {UID:7}]);
@@ -104,7 +104,7 @@ describe('bplist-parser', function () {
 
     const [dict] = await bplist.parseFile(file);
     const endTime = new Date();
-    console.log('Parsed "' + file + '" in ' + (endTime - startTime) + 'ms');
+    console.log('Parsed "' + file + '" in ' + (endTime.getTime() - startTime.getTime()) + 'ms');
 
     assert.equal(dict['zero'], '0');
     assert.equal(dict['int32item'], '1234567890');
@@ -154,7 +154,9 @@ describe('bplist-parser', function () {
   });
 });
 
-function makeIntegerArray(cases) {
+type IntegerCase = { value: bigint; bytes: number; expected: number | bigint };
+
+function makeIntegerArray(cases: IntegerCase[]): Buffer {
   if (cases.length >= 15) {
     throw new Error('test helper only supports short arrays');
   }
@@ -165,7 +167,7 @@ function makeIntegerArray(cases) {
     ...cases.map((_, index) => writeUIntBE(index + 1, objectRefSize))
   ]);
   const objects = [root, ...cases.map(({value, bytes}) => makeIntegerObject(value, bytes))];
-  const offsets = [];
+  const offsets: number[] = [];
   let offset = 8;
 
   for (const object of objects) {
@@ -192,8 +194,8 @@ function makeIntegerArray(cases) {
   ]);
 }
 
-function makeIntegerObject(value, byteLength) {
-  const widthInfo = {
+function makeIntegerObject(value: bigint, byteLength: number): Buffer {
+  const widthInfo: Record<number, number> = {
     1: 0,
     2: 1,
     4: 2,
@@ -210,7 +212,7 @@ function makeIntegerObject(value, byteLength) {
   ]);
 }
 
-function writeUIntBE(value, byteLength) {
+function writeUIntBE(value: bigint | number, byteLength: number): Buffer {
   let integer = BigInt(value);
 
   if (integer < 0n) {
@@ -225,7 +227,7 @@ function writeUIntBE(value, byteLength) {
   return buffer;
 }
 
-function byteWidth(value) {
+function byteWidth(value: number): number {
   if (value <= 0xff) {
     return 1;
   }
diff --git a/tsconfig.build.json b/tsconfig.build.json
new file mode 100644
index 0000000..b2009a7
--- /dev/null
+++ b/tsconfig.build.json
@@ -0,0 +1,10 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "declaration": true,
+    "emitDeclarationOnly": true,
+    "noEmit": false,
+    "outDir": "dist/types"
+  },
+  "include": ["bplistParser.ts"]
+}
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..d5ba5b5
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,12 @@
+{
+  "compilerOptions": {
+    "strict": true,
+    "target": "ES2022",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "skipLibCheck": true,
+    "types": ["node"],
+    "noEmit": true
+  },
+  "include": ["bplistParser.ts", "test/**/*.ts"]
+}