diff --git a/bin/pbf b/bin/pbf
index 7981f06..aabd240 100755
--- a/bin/pbf
+++ b/bin/pbf
@@ -4,13 +4,14 @@ import resolve from 'resolve-protobuf-schema';
 import {compileRaw} from '../compile.js';
 
 if (process.argv.length < 3) {
-    console.error('Usage: pbf [file.proto] [--no-read] [--no-write] [--legacy]');
+    console.error('Usage: pbf [file.proto] [--no-read] [--no-write] [--jsdoc] [--legacy]');
     process.exit(0);
 }
 
 const code = compileRaw(resolve.sync(process.argv[2]), {
     noRead: process.argv.indexOf('--no-read') >= 0,
     noWrite: process.argv.indexOf('--no-write') >= 0,
+    jsDoc: process.argv.indexOf('--jsdoc') >= 0,
     legacy: process.argv.indexOf('--legacy') >= 0
 });
 
diff --git a/compile.js b/compile.js
index 220de6d..e88de58 100644
--- a/compile.js
+++ b/compile.js
@@ -9,7 +9,13 @@ export function compile(proto) {
 
 export function compileRaw(proto, options = {}) {
     const context = buildDefaults(buildContext(proto, null), proto.syntax);
-    return `${options.dev ? '' : `// code generated by pbf v${version}\n`}${writeContext(context, options)}`;
+
+    let output = options.dev ? '' : `// code generated by pbf v${version}\n`;
+    if (options.jsDoc) {
+        output += typeDef(`import("${options.dev ? '../../index.js' : 'pbf'}").default`, 'Pbf');
+    }
+    output += writeContext(context, options);
+    return output;
 }
 
 function writeContext(ctx, options) {
@@ -24,12 +30,20 @@ function writeContext(ctx, options) {
 }
 
 function writeMessage(ctx, options) {
+    const name = ctx._name;
     const fields = ctx._proto.fields;
 
     let code = '\n';
 
+    if (options.jsDoc) {
+        code += compileObjectType(name, fields);
+    }
+
     if (!options.noRead) {
-        const readName = `read${ctx._name}`;
+        const readName = `read${name}`;
+        if (options.jsDoc) {
+            code += ['\n/**', ' * @param {Pbf} pbf', ' * @param {number} [end]', ` * @returns {${name}}`, ' */'].join('\n').concat('\n');
+        }
         code +=
 `${writeFunctionExport(options, readName)}function ${readName}(pbf, end) {
     return pbf.readFields(${readName}Field, ${compileDest(ctx)}, end);
@@ -60,7 +74,12 @@ function ${readName}Field(tag, obj, pbf) {
     }
 
     if (!options.noWrite) {
-        const writeName = `write${ctx._name}`;
+        const writeName = `write${name}`;
+
+        if (options.jsDoc) {
+            code += ['\n/**', ` * @param {${name}} obj`, ' * @param {Pbf} pbf', ' */'].join('\n').concat('\n');
+        }
+
         code += `${writeFunctionExport(options, writeName)}function ${writeName}(obj, pbf) {\n`;
         for (const field of fields) {
             const writeCode =
@@ -90,7 +109,10 @@ function getEnumValues(ctx) {
 function writeEnum(ctx, {legacy}) {
     const enums = JSON.stringify(getEnumValues(ctx), null, 4);
     const name = ctx._name;
-    return `\n${legacy ? `const ${name} = exports.${name}` : `export const ${name}`} = ${enums};\n`;
+
+    let output = '\n/** @enum {number} */';
+    output += `\n${legacy ? `const ${name} = exports.${name}` : `export const ${name}`} = ${enums};\n`;
+    return output;
 }
 
 function compileDest(ctx) {
@@ -114,23 +136,27 @@ function getType(ctx, field) {
     return path.reduce((ctx, name) => ctx && ctx[name], ctx);
 }
 
+function fieldTypeIsNumber(field) {
+    switch (field.type) {
+    case 'float':
+    case 'double':
+    case 'uint32':
+    case 'uint64':
+    case 'int32':
+    case 'int64':
+    case 'sint32':
+    case 'sint64':
+    case 'fixed32':
+    case 'fixed64':
+    case 'sfixed32':
+    case 'sfixed64': return true;
+    default: return false;
+    }
+}
+
 function fieldShouldUseStringAsNumber(field) {
     if (field.options.jstype === 'JS_STRING') {
-        switch (field.type) {
-        case 'float':
-        case 'double':
-        case 'uint32':
-        case 'uint64':
-        case 'int32':
-        case 'int64':
-        case 'sint32':
-        case 'sint64':
-        case 'fixed32':
-        case 'fixed64':
-        case 'sfixed32':
-        case 'sfixed64': return true;
-        default:         return false;
-        }
+        return fieldTypeIsNumber(field);
     }
     return false;
 }
@@ -415,3 +441,42 @@ function getDefaultWriteTest(ctx, field) {
 function isPacked(field) {
     return field.options.packed === 'true';
 }
+
+/**
+ * @param {{type: string}} field
+ * @returns {string}
+ */
+function getFieldType(field) {
+    let type = field.type;
+    if (fieldTypeIsNumber(field)) type = 'number';
+    if (field.type === 'bool') type = 'boolean';
+    if (field.type === 'bytes') type = 'Uint8Array';
+    return field.repeated ? `Array<${type}>` : type;
+}
+
+/**
+ * @param {string} type
+ * @param {string} name
+ * @param {{name: string; type: string; required: boolean}} [fields]
+ * @returns {string}
+ */
+function typeDef(type, name, fields = []) {
+    const properties = fields.map((field) => {
+        const type = getFieldType(field);
+        const name = field.required ? field.name : `[${field.name}]`;
+        return ` * @property {${type}} ${name}`;
+    });
+
+    return ['/**', ` * @typedef {${type}} ${name}`, ...properties, ' */']
+        .join('\n')
+        .concat('\n');
+}
+
+/**
+ * @param {string} name
+ * @param {{name: string; type: string; required: boolean}} [fields]
+ * @returns {string}
+ */
+function compileObjectType(name, fields = []) {
+    return typeDef('object', name, fields);
+}
diff --git a/package-lock.json b/package-lock.json
index 5f57878..441b90e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -8,6 +8,9 @@
       "name": "pbf",
       "version": "4.0.1",
       "license": "BSD-3-Clause",
+      "workspaces": [
+        "test/typescript/"
+      ],
       "dependencies": {
         "resolve-protobuf-schema": "^2.1.0"
       },
@@ -1760,6 +1763,14 @@
         "node": ">=8"
       }
     },
+    "node_modules/pbf": {
+      "resolved": "",
+      "link": true
+    },
+    "node_modules/pbf-ts": {
+      "resolved": "test/typescript",
+      "link": true
+    },
     "node_modules/performance-now": {
       "version": "2.1.0",
       "resolved": "https://registry.npmjs.org/performance-now/-/performance-now-2.1.0.tgz",
@@ -2441,6 +2452,14 @@
       "funding": {
         "url": "https://github.com/sponsors/sindresorhus"
       }
+    },
+    "test/typescript": {
+      "dependencies": {
+        "pbf": "file:../../"
+      },
+      "devDependencies": {
+        "typescript": "^5.5.3"
+      }
     }
   }
 }
diff --git a/package.json b/package.json
index 499b0f6..8e4e76a 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
   "scripts": {
     "bench": "node bench/bench.js",
     "pretest": "eslint *.js compile.js test/*.js test/fixtures/*.js bin/pbf",
-    "test": "tsc && node --test",
+    "test": "tsc && node --test && tsc --allowJs --checkJs --noEmit --isolatedModules test/fixtures/*.js",
     "cov": "node --test --experimental-test-covetage",
     "build": "rollup -c",
     "prepublishOnly": "npm run test && npm run build"
@@ -60,5 +60,8 @@
     "rollup": "^4.18.0",
     "tile-stats-runner": "^1.0.0",
     "typescript": "^5.5.3"
-  }
+  },
+  "workspaces": [
+    "test/typescript/"
+  ]
 }
diff --git a/test/compile.test.js b/test/compile.test.js
index d2e5157..2bba661 100644
--- a/test/compile.test.js
+++ b/test/compile.test.js
@@ -12,7 +12,7 @@ test('compiles all proto files to proper js', () => {
     for (const path of files) {
         if (!path.endsWith('.proto')) continue;
         const proto = resolve(new URL(`fixtures/${path}`, import.meta.url));
-        const js = compileRaw(proto, {dev: true});
+        const js = compileRaw(proto, {dev: true, jsDoc: true});
 
         // uncomment to update the fixtures
         // fs.writeFileSync(new URL(`fixtures/${path}`.replace('.proto', '.js'), import.meta.url), js);
diff --git a/test/fixtures/defaults.js b/test/fixtures/defaults.js
index bf0ef32..24ecf66 100644
--- a/test/fixtures/defaults.js
+++ b/test/fixtures/defaults.js
@@ -1,9 +1,27 @@
+/**
+ * @typedef {import("../../index.js").default} Pbf
+ */
 
+/** @enum {number} */
 export const MessageType = {
     "UNKNOWN": 0,
     "GREETING": 1
 };
 
+/**
+ * @typedef {object} Envelope
+ * @property {MessageType} [type]
+ * @property {string} [name]
+ * @property {boolean} [flag]
+ * @property {number} [weight]
+ * @property {number} [id]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {Envelope}
+ */
 export function readEnvelope(pbf, end) {
     return pbf.readFields(readEnvelopeField, {type: 1, name: "test", flag: true, weight: 1.5, id: 1}, end);
 }
@@ -14,6 +32,11 @@ function readEnvelopeField(tag, obj, pbf) {
     else if (tag === 4) obj.weight = pbf.readFloat();
     else if (tag === 5) obj.id = pbf.readVarint(true);
 }
+
+/**
+ * @param {Envelope} obj
+ * @param {Pbf} pbf
+ */
 export function writeEnvelope(obj, pbf) {
     if (obj.type != null && obj.type !== 1) pbf.writeVarintField(1, obj.type);
     if (obj.name != null && obj.name !== "test") pbf.writeStringField(2, obj.name);
diff --git a/test/fixtures/defaults_implicit.js b/test/fixtures/defaults_implicit.js
index 5603350..5c4962b 100644
--- a/test/fixtures/defaults_implicit.js
+++ b/test/fixtures/defaults_implicit.js
@@ -1,17 +1,54 @@
+/**
+ * @typedef {import("../../index.js").default} Pbf
+ */
 
+/** @enum {number} */
 export const MessageType = {
     "UNKNOWN": 0,
     "GREETING": 1
 };
 
+/**
+ * @typedef {object} CustomType
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {CustomType}
+ */
 export function readCustomType(pbf, end) {
     return pbf.readFields(readCustomTypeField, {}, end);
 }
 function readCustomTypeField(tag, obj, pbf) {
 }
+
+/**
+ * @param {CustomType} obj
+ * @param {Pbf} pbf
+ */
 export function writeCustomType(obj, pbf) {
 }
 
+/**
+ * @typedef {object} Envelope
+ * @property {MessageType} [type]
+ * @property {string} [name]
+ * @property {boolean} [flag]
+ * @property {number} [weight]
+ * @property {number} [id]
+ * @property {Array<string>} [tags]
+ * @property {Array<number>} [numbers]
+ * @property {Uint8Array} [bytes]
+ * @property {CustomType} [custom]
+ * @property {Array<MessageType>} [types]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {Envelope}
+ */
 export function readEnvelope(pbf, end) {
     return pbf.readFields(readEnvelopeField, {type: 0, name: "", flag: false, weight: 0, id: 0, tags: [], numbers: [], bytes: undefined, custom: undefined, types: []}, end);
 }
@@ -27,6 +64,11 @@ function readEnvelopeField(tag, obj, pbf) {
     else if (tag === 9) obj.custom = readCustomType(pbf, pbf.readVarint() + pbf.pos);
     else if (tag === 10) pbf.readPackedVarint(obj.types);
 }
+
+/**
+ * @param {Envelope} obj
+ * @param {Pbf} pbf
+ */
 export function writeEnvelope(obj, pbf) {
     if (obj.type) pbf.writeVarintField(1, obj.type);
     if (obj.name) pbf.writeStringField(2, obj.name);
diff --git a/test/fixtures/defaults_proto3.js b/test/fixtures/defaults_proto3.js
index 57748fb..0ef2f79 100644
--- a/test/fixtures/defaults_proto3.js
+++ b/test/fixtures/defaults_proto3.js
@@ -1,9 +1,27 @@
+/**
+ * @typedef {import("../../index.js").default} Pbf
+ */
 
+/** @enum {number} */
 export const MessageType = {
     "UNKNOWN": 0,
     "GREETING": 1
 };
 
+/**
+ * @typedef {object} Envelope
+ * @property {MessageType} [type]
+ * @property {string} [name]
+ * @property {boolean} [flag]
+ * @property {number} [weight]
+ * @property {number} [id]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {Envelope}
+ */
 export function readEnvelope(pbf, end) {
     return pbf.readFields(readEnvelopeField, {type: 0, name: "", flag: false, weight: 0, id: 0}, end);
 }
@@ -14,6 +32,11 @@ function readEnvelopeField(tag, obj, pbf) {
     else if (tag === 4) obj.weight = pbf.readFloat();
     else if (tag === 5) obj.id = pbf.readVarint(true);
 }
+
+/**
+ * @param {Envelope} obj
+ * @param {Pbf} pbf
+ */
 export function writeEnvelope(obj, pbf) {
     if (obj.type) pbf.writeVarintField(1, obj.type);
     if (obj.name) pbf.writeStringField(2, obj.name);
diff --git a/test/fixtures/embedded_type.js b/test/fixtures/embedded_type.js
index 4c41ddf..53dde28 100644
--- a/test/fixtures/embedded_type.js
+++ b/test/fixtures/embedded_type.js
@@ -1,4 +1,19 @@
+/**
+ * @typedef {import("../../index.js").default} Pbf
+ */
 
+/**
+ * @typedef {object} EmbeddedType
+ * @property {string} [value]
+ * @property {Container} [sub_field]
+ * @property {Container.Inner} [sub_sub_field]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {EmbeddedType}
+ */
 export function readEmbeddedType(pbf, end) {
     return pbf.readFields(readEmbeddedTypeField, {value: "test", sub_field: undefined, sub_sub_field: undefined}, end);
 }
@@ -7,28 +22,63 @@ function readEmbeddedTypeField(tag, obj, pbf) {
     else if (tag === 4) obj.sub_field = readEmbeddedTypeContainer(pbf, pbf.readVarint() + pbf.pos);
     else if (tag === 5) obj.sub_sub_field = readEmbeddedTypeContainerInner(pbf, pbf.readVarint() + pbf.pos);
 }
+
+/**
+ * @param {EmbeddedType} obj
+ * @param {Pbf} pbf
+ */
 export function writeEmbeddedType(obj, pbf) {
     if (obj.value != null && obj.value !== "test") pbf.writeStringField(1, obj.value);
     if (obj.sub_field) pbf.writeMessage(4, writeEmbeddedTypeContainer, obj.sub_field);
     if (obj.sub_sub_field) pbf.writeMessage(5, writeEmbeddedTypeContainerInner, obj.sub_sub_field);
 }
 
+/**
+ * @typedef {object} EmbeddedTypeContainer
+ * @property {Array<Inner>} [values]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {EmbeddedTypeContainer}
+ */
 export function readEmbeddedTypeContainer(pbf, end) {
     return pbf.readFields(readEmbeddedTypeContainerField, {values: []}, end);
 }
 function readEmbeddedTypeContainerField(tag, obj, pbf) {
     if (tag === 1) obj.values.push(readEmbeddedTypeContainerInner(pbf, pbf.readVarint() + pbf.pos));
 }
+
+/**
+ * @param {EmbeddedTypeContainer} obj
+ * @param {Pbf} pbf
+ */
 export function writeEmbeddedTypeContainer(obj, pbf) {
     if (obj.values) for (const item of obj.values) pbf.writeMessage(1, writeEmbeddedTypeContainerInner, item);
 }
 
+/**
+ * @typedef {object} EmbeddedTypeContainerInner
+ * @property {string} [value]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {EmbeddedTypeContainerInner}
+ */
 export function readEmbeddedTypeContainerInner(pbf, end) {
     return pbf.readFields(readEmbeddedTypeContainerInnerField, {value: ""}, end);
 }
 function readEmbeddedTypeContainerInnerField(tag, obj, pbf) {
     if (tag === 1) obj.value = pbf.readString();
 }
+
+/**
+ * @param {EmbeddedTypeContainerInner} obj
+ * @param {Pbf} pbf
+ */
 export function writeEmbeddedTypeContainerInner(obj, pbf) {
     if (obj.value) pbf.writeStringField(1, obj.value);
 }
diff --git a/test/fixtures/map.js b/test/fixtures/map.js
index 793d26c..a480bfc 100644
--- a/test/fixtures/map.js
+++ b/test/fixtures/map.js
@@ -1,4 +1,18 @@
+/**
+ * @typedef {import("../../index.js").default} Pbf
+ */
 
+/**
+ * @typedef {object} Envelope
+ * @property {map} [kv]
+ * @property {map} [kn]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {Envelope}
+ */
 export function readEnvelope(pbf, end) {
     return pbf.readFields(readEnvelopeField, {kv: {}, kn: {}}, end);
 }
@@ -6,11 +20,27 @@ function readEnvelopeField(tag, obj, pbf) {
     if (tag === 1) { const {key, value} = readEnvelope_FieldEntry1(pbf, pbf.readVarint() + pbf.pos); obj.kv[key] = value; }
     else if (tag === 2) { const {key, value} = readEnvelope_FieldEntry2(pbf, pbf.readVarint() + pbf.pos); obj.kn[key] = value; }
 }
+
+/**
+ * @param {Envelope} obj
+ * @param {Pbf} pbf
+ */
 export function writeEnvelope(obj, pbf) {
     if (obj.kv) for (const key of Object.keys(obj.kv)) pbf.writeMessage(1, writeEnvelope_FieldEntry1, {key, value: obj.kv[key]});
     if (obj.kn) for (const key of Object.keys(obj.kn)) pbf.writeMessage(2, writeEnvelope_FieldEntry2, {key, value: obj.kn[key]});
 }
 
+/**
+ * @typedef {object} Envelope_FieldEntry1
+ * @property {string} [key]
+ * @property {string} [value]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {Envelope_FieldEntry1}
+ */
 export function readEnvelope_FieldEntry1(pbf, end) {
     return pbf.readFields(readEnvelope_FieldEntry1Field, {key: "", value: ""}, end);
 }
@@ -18,11 +48,27 @@ function readEnvelope_FieldEntry1Field(tag, obj, pbf) {
     if (tag === 1) obj.key = pbf.readString();
     else if (tag === 2) obj.value = pbf.readString();
 }
+
+/**
+ * @param {Envelope_FieldEntry1} obj
+ * @param {Pbf} pbf
+ */
 export function writeEnvelope_FieldEntry1(obj, pbf) {
     if (obj.key) pbf.writeStringField(1, obj.key);
     if (obj.value) pbf.writeStringField(2, obj.value);
 }
 
+/**
+ * @typedef {object} Envelope_FieldEntry2
+ * @property {string} [key]
+ * @property {number} [value]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {Envelope_FieldEntry2}
+ */
 export function readEnvelope_FieldEntry2(pbf, end) {
     return pbf.readFields(readEnvelope_FieldEntry2Field, {key: "", value: 0}, end);
 }
@@ -30,6 +76,11 @@ function readEnvelope_FieldEntry2Field(tag, obj, pbf) {
     if (tag === 1) obj.key = pbf.readString();
     else if (tag === 2) obj.value = pbf.readVarint(true);
 }
+
+/**
+ * @param {Envelope_FieldEntry2} obj
+ * @param {Pbf} pbf
+ */
 export function writeEnvelope_FieldEntry2(obj, pbf) {
     if (obj.key) pbf.writeStringField(1, obj.key);
     if (obj.value) pbf.writeVarintField(2, obj.value);
diff --git a/test/fixtures/oneof.js b/test/fixtures/oneof.js
index 5055689..95c76b8 100644
--- a/test/fixtures/oneof.js
+++ b/test/fixtures/oneof.js
@@ -1,4 +1,20 @@
+/**
+ * @typedef {import("../../index.js").default} Pbf
+ */
 
+/**
+ * @typedef {object} Envelope
+ * @property {number} [id]
+ * @property {number} [int]
+ * @property {number} [float]
+ * @property {string} [string]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {Envelope}
+ */
 export function readEnvelope(pbf, end) {
     return pbf.readFields(readEnvelopeField, {id: 0, int: 0, value: undefined, float: 0, string: ""}, end);
 }
@@ -8,6 +24,11 @@ function readEnvelopeField(tag, obj, pbf) {
     else if (tag === 3) { obj.float = pbf.readFloat(); obj.value = "float"; }
     else if (tag === 4) { obj.string = pbf.readString(); obj.value = "string"; }
 }
+
+/**
+ * @param {Envelope} obj
+ * @param {Pbf} pbf
+ */
 export function writeEnvelope(obj, pbf) {
     if (obj.id) pbf.writeVarintField(1, obj.id);
     if (obj.int != null) pbf.writeVarintField(2, obj.int);
diff --git a/test/fixtures/packed.js b/test/fixtures/packed.js
index 6780737..e343e2a 100644
--- a/test/fixtures/packed.js
+++ b/test/fixtures/packed.js
@@ -1,4 +1,18 @@
+/**
+ * @typedef {import("../../index.js").default} Pbf
+ */
 
+/**
+ * @typedef {object} NotPacked
+ * @property {Array<number>} [value]
+ * @property {Array<number>} [types]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {NotPacked}
+ */
 export function readNotPacked(pbf, end) {
     return pbf.readFields(readNotPackedField, {value: [], types: []}, end);
 }
@@ -6,11 +20,27 @@ function readNotPackedField(tag, obj, pbf) {
     if (tag === 1) pbf.readPackedVarint(obj.value, true);
     else if (tag === 2) pbf.readPackedVarint(obj.types, true);
 }
+
+/**
+ * @param {NotPacked} obj
+ * @param {Pbf} pbf
+ */
 export function writeNotPacked(obj, pbf) {
     if (obj.value) for (const item of obj.value) pbf.writeVarintField(1, item);
     if (obj.types) for (const item of obj.types) pbf.writeVarintField(2, item);
 }
 
+/**
+ * @typedef {object} FalsePacked
+ * @property {Array<number>} [value]
+ * @property {Array<number>} [types]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {FalsePacked}
+ */
 export function readFalsePacked(pbf, end) {
     return pbf.readFields(readFalsePackedField, {value: [], types: []}, end);
 }
@@ -18,11 +48,27 @@ function readFalsePackedField(tag, obj, pbf) {
     if (tag === 1) pbf.readPackedVarint(obj.value, true);
     else if (tag === 2) pbf.readPackedVarint(obj.types, true);
 }
+
+/**
+ * @param {FalsePacked} obj
+ * @param {Pbf} pbf
+ */
 export function writeFalsePacked(obj, pbf) {
     if (obj.value) for (const item of obj.value) pbf.writeVarintField(1, item);
     if (obj.types) for (const item of obj.types) pbf.writeVarintField(2, item);
 }
 
+/**
+ * @typedef {object} Packed
+ * @property {Array<number>} [value]
+ * @property {Array<number>} [types]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {Packed}
+ */
 export function readPacked(pbf, end) {
     return pbf.readFields(readPackedField, {value: [], types: []}, end);
 }
@@ -30,6 +76,11 @@ function readPackedField(tag, obj, pbf) {
     if (tag === 1) pbf.readPackedVarint(obj.value, true);
     else if (tag === 2) pbf.readPackedVarint(obj.types, true);
 }
+
+/**
+ * @param {Packed} obj
+ * @param {Pbf} pbf
+ */
 export function writePacked(obj, pbf) {
     if (obj.value) pbf.writePackedVarint(1, obj.value);
     if (obj.types) pbf.writePackedVarint(2, obj.types);
diff --git a/test/fixtures/packed_proto3.js b/test/fixtures/packed_proto3.js
index 3584f4d..e47ca68 100644
--- a/test/fixtures/packed_proto3.js
+++ b/test/fixtures/packed_proto3.js
@@ -1,9 +1,24 @@
+/**
+ * @typedef {import("../../index.js").default} Pbf
+ */
 
+/** @enum {number} */
 export const MessageType = {
     "UNKNOWN": 0,
     "GREETING": 1
 };
 
+/**
+ * @typedef {object} NotPacked
+ * @property {Array<number>} [value]
+ * @property {Array<MessageType>} [types]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {NotPacked}
+ */
 export function readNotPacked(pbf, end) {
     return pbf.readFields(readNotPackedField, {value: [], types: []}, end);
 }
@@ -11,11 +26,27 @@ function readNotPackedField(tag, obj, pbf) {
     if (tag === 1) pbf.readPackedVarint(obj.value, true);
     else if (tag === 2) pbf.readPackedVarint(obj.types);
 }
+
+/**
+ * @param {NotPacked} obj
+ * @param {Pbf} pbf
+ */
 export function writeNotPacked(obj, pbf) {
     if (obj.value) pbf.writePackedVarint(1, obj.value);
     if (obj.types) pbf.writePackedVarint(2, obj.types);
 }
 
+/**
+ * @typedef {object} FalsePacked
+ * @property {Array<number>} [value]
+ * @property {Array<MessageType>} [types]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {FalsePacked}
+ */
 export function readFalsePacked(pbf, end) {
     return pbf.readFields(readFalsePackedField, {value: [], types: []}, end);
 }
@@ -23,17 +54,37 @@ function readFalsePackedField(tag, obj, pbf) {
     if (tag === 1) pbf.readPackedVarint(obj.value, true);
     else if (tag === 2) pbf.readPackedVarint(obj.types);
 }
+
+/**
+ * @param {FalsePacked} obj
+ * @param {Pbf} pbf
+ */
 export function writeFalsePacked(obj, pbf) {
     if (obj.value) for (const item of obj.value) pbf.writeVarintField(1, item);
     if (obj.types) for (const item of obj.types) pbf.writeVarintField(2, item);
 }
 
+/**
+ * @typedef {object} Packed
+ * @property {Array<number>} [value]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {Packed}
+ */
 export function readPacked(pbf, end) {
     return pbf.readFields(readPackedField, {value: []}, end);
 }
 function readPackedField(tag, obj, pbf) {
     if (tag === 16) pbf.readPackedVarint(obj.value, true);
 }
+
+/**
+ * @param {Packed} obj
+ * @param {Pbf} pbf
+ */
 export function writePacked(obj, pbf) {
     if (obj.value) pbf.writePackedVarint(16, obj.value);
 }
diff --git a/test/fixtures/type_string.js b/test/fixtures/type_string.js
index 9c16b01..dabbf05 100644
--- a/test/fixtures/type_string.js
+++ b/test/fixtures/type_string.js
@@ -1,4 +1,22 @@
+/**
+ * @typedef {import("../../index.js").default} Pbf
+ */
 
+/**
+ * @typedef {object} TypeString
+ * @property {number} [int]
+ * @property {number} [long]
+ * @property {boolean} [boolVal]
+ * @property {number} [float]
+ * @property {number} [default_implicit]
+ * @property {number} [default_explicit]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {TypeString}
+ */
 export function readTypeString(pbf, end) {
     return pbf.readFields(readTypeStringField, {int: "0", long: "0", boolVal: false, float: "0", default_implicit: "0", default_explicit: "42"}, end);
 }
@@ -10,6 +28,11 @@ function readTypeStringField(tag, obj, pbf) {
     else if (tag === 5) obj.default_implicit = pbf.readVarint(true).toString();
     else if (tag === 6) obj.default_explicit = pbf.readVarint(true).toString();
 }
+
+/**
+ * @param {TypeString} obj
+ * @param {Pbf} pbf
+ */
 export function writeTypeString(obj, pbf) {
     if (obj.int != null && obj.int !== "0") pbf.writeVarintField(1, parseInt(obj.int, 10));
     if (obj.long != null && obj.long !== "0") pbf.writeVarintField(2, parseInt(obj.long, 10));
@@ -19,6 +42,19 @@ export function writeTypeString(obj, pbf) {
     if (obj.default_explicit != null && obj.default_explicit !== "42") pbf.writeVarintField(6, parseInt(obj.default_explicit, 10));
 }
 
+/**
+ * @typedef {object} TypeNotString
+ * @property {number} [int]
+ * @property {number} [long]
+ * @property {boolean} [boolVal]
+ * @property {number} [float]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {TypeNotString}
+ */
 export function readTypeNotString(pbf, end) {
     return pbf.readFields(readTypeNotStringField, {int: 0, long: 0, boolVal: false, float: 0}, end);
 }
@@ -28,6 +64,11 @@ function readTypeNotStringField(tag, obj, pbf) {
     else if (tag === 3) obj.boolVal = pbf.readBoolean();
     else if (tag === 4) obj.float = pbf.readFloat();
 }
+
+/**
+ * @param {TypeNotString} obj
+ * @param {Pbf} pbf
+ */
 export function writeTypeNotString(obj, pbf) {
     if (obj.int) pbf.writeVarintField(1, obj.int);
     if (obj.long) pbf.writeVarintField(2, obj.long);
diff --git a/test/fixtures/varint.js b/test/fixtures/varint.js
index 7cebe50..a7ef3c4 100644
--- a/test/fixtures/varint.js
+++ b/test/fixtures/varint.js
@@ -1,4 +1,20 @@
+/**
+ * @typedef {import("../../index.js").default} Pbf
+ */
 
+/**
+ * @typedef {object} Envelope
+ * @property {number} [int]
+ * @property {number} [uint]
+ * @property {number} [long]
+ * @property {number} [ulong]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {Envelope}
+ */
 export function readEnvelope(pbf, end) {
     return pbf.readFields(readEnvelopeField, {int: 0, uint: 0, long: 0, ulong: 0}, end);
 }
@@ -8,6 +24,11 @@ function readEnvelopeField(tag, obj, pbf) {
     else if (tag === 3) obj.long = pbf.readVarint(true);
     else if (tag === 4) obj.ulong = pbf.readVarint();
 }
+
+/**
+ * @param {Envelope} obj
+ * @param {Pbf} pbf
+ */
 export function writeEnvelope(obj, pbf) {
     if (obj.int) pbf.writeVarintField(1, obj.int);
     if (obj.uint) pbf.writeVarintField(2, obj.uint);
diff --git a/test/fixtures/vector_tile.js b/test/fixtures/vector_tile.js
index 5796828..433aa3f 100644
--- a/test/fixtures/vector_tile.js
+++ b/test/fixtures/vector_tile.js
@@ -1,14 +1,33 @@
+/**
+ * @typedef {import("../../index.js").default} Pbf
+ */
 
+/**
+ * @typedef {object} Tile
+ * @property {Array<Layer>} [layers]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {Tile}
+ */
 export function readTile(pbf, end) {
     return pbf.readFields(readTileField, {layers: []}, end);
 }
 function readTileField(tag, obj, pbf) {
     if (tag === 3) obj.layers.push(readTileLayer(pbf, pbf.readVarint() + pbf.pos));
 }
+
+/**
+ * @param {Tile} obj
+ * @param {Pbf} pbf
+ */
 export function writeTile(obj, pbf) {
     if (obj.layers) for (const item of obj.layers) pbf.writeMessage(3, writeTileLayer, item);
 }
 
+/** @enum {number} */
 export const TileGeomType = {
     "UNKNOWN": 0,
     "POINT": 1,
@@ -16,6 +35,22 @@ export const TileGeomType = {
     "POLYGON": 3
 };
 
+/**
+ * @typedef {object} TileValue
+ * @property {string} [string_value]
+ * @property {number} [float_value]
+ * @property {number} [double_value]
+ * @property {number} [int_value]
+ * @property {number} [uint_value]
+ * @property {number} [sint_value]
+ * @property {boolean} [bool_value]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {TileValue}
+ */
 export function readTileValue(pbf, end) {
     return pbf.readFields(readTileValueField, {string_value: "", float_value: 0, double_value: 0, int_value: 0, uint_value: 0, sint_value: 0, bool_value: false}, end);
 }
@@ -28,6 +63,11 @@ function readTileValueField(tag, obj, pbf) {
     else if (tag === 6) obj.sint_value = pbf.readSVarint();
     else if (tag === 7) obj.bool_value = pbf.readBoolean();
 }
+
+/**
+ * @param {TileValue} obj
+ * @param {Pbf} pbf
+ */
 export function writeTileValue(obj, pbf) {
     if (obj.string_value) pbf.writeStringField(1, obj.string_value);
     if (obj.float_value) pbf.writeFloatField(2, obj.float_value);
@@ -38,6 +78,19 @@ export function writeTileValue(obj, pbf) {
     if (obj.bool_value) pbf.writeBooleanField(7, obj.bool_value);
 }
 
+/**
+ * @typedef {object} TileFeature
+ * @property {number} [id]
+ * @property {Array<number>} [tags]
+ * @property {GeomType} [type]
+ * @property {Array<number>} [geometry]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {TileFeature}
+ */
 export function readTileFeature(pbf, end) {
     return pbf.readFields(readTileFeatureField, {id: 0, tags: [], type: 0, geometry: []}, end);
 }
@@ -47,6 +100,11 @@ function readTileFeatureField(tag, obj, pbf) {
     else if (tag === 3) obj.type = pbf.readVarint();
     else if (tag === 4) pbf.readPackedVarint(obj.geometry);
 }
+
+/**
+ * @param {TileFeature} obj
+ * @param {Pbf} pbf
+ */
 export function writeTileFeature(obj, pbf) {
     if (obj.id) pbf.writeVarintField(1, obj.id);
     if (obj.tags) pbf.writePackedVarint(2, obj.tags);
@@ -54,6 +112,21 @@ export function writeTileFeature(obj, pbf) {
     if (obj.geometry) pbf.writePackedVarint(4, obj.geometry);
 }
 
+/**
+ * @typedef {object} TileLayer
+ * @property {number} version
+ * @property {string} name
+ * @property {Array<Feature>} [features]
+ * @property {Array<string>} [keys]
+ * @property {Array<Value>} [values]
+ * @property {number} [extent]
+ */
+
+/**
+ * @param {Pbf} pbf
+ * @param {number} [end]
+ * @returns {TileLayer}
+ */
 export function readTileLayer(pbf, end) {
     return pbf.readFields(readTileLayerField, {version: 1, name: "", features: [], keys: [], values: [], extent: 4096}, end);
 }
@@ -65,6 +138,11 @@ function readTileLayerField(tag, obj, pbf) {
     else if (tag === 4) obj.values.push(readTileValue(pbf, pbf.readVarint() + pbf.pos));
     else if (tag === 5) obj.extent = pbf.readVarint();
 }
+
+/**
+ * @param {TileLayer} obj
+ * @param {Pbf} pbf
+ */
 export function writeTileLayer(obj, pbf) {
     if (obj.version != null && obj.version !== 1) pbf.writeVarintField(15, obj.version);
     if (obj.name) pbf.writeStringField(1, obj.name);
diff --git a/test/typescript/defaults.ts b/test/typescript/defaults.ts
new file mode 100644
index 0000000..fe05384
--- /dev/null
+++ b/test/typescript/defaults.ts
@@ -0,0 +1,28 @@
+import Pbf from 'pbf';
+
+import {readEnvelope, writeEnvelope, MessageType} from '../fixtures/defaults.js'
+import type {Envelope} from '../fixtures/defaults.js'
+
+const pbf = new Pbf();
+readEnvelope(pbf) satisfies Envelope;
+
+const valid: Envelope = {
+    type: MessageType.GREETING,
+    name: 'test',
+    flag: true,
+    weight: 1.5,
+    id: 1,
+};
+
+const invalid = {
+    type: null,
+    name: null,
+    flag: null,
+    weight: null,
+    id: null,
+};
+
+writeEnvelope(valid, pbf);
+
+// @ts-expect-error
+writeEnvelope(invalid, pbf);
diff --git a/test/typescript/defaults_implicit.ts b/test/typescript/defaults_implicit.ts
new file mode 100644
index 0000000..ddcca98
--- /dev/null
+++ b/test/typescript/defaults_implicit.ts
@@ -0,0 +1,38 @@
+import Pbf from 'pbf';
+
+import {readEnvelope, writeEnvelope, MessageType} from '../fixtures/defaults_implicit.js'
+import type {Envelope, CustomType} from '../fixtures/defaults_implicit.js'
+
+const pbf = new Pbf();
+readEnvelope(pbf) satisfies Envelope;
+
+const valid: Envelope = {
+    type: MessageType.GREETING,
+    name: 'test',
+    flag: true,
+    weight: 1.5,
+    id: 1,
+    tags: [''],
+    numbers: [0],
+    bytes: new Uint8Array(0),
+    custom: {} satisfies CustomType,
+    types: [MessageType.GREETING],
+};
+
+const invalid = {
+    type: null,
+    name: null,
+    flag: null,
+    weight: null,
+    id: null,
+    tags: null,
+    numbers: null,
+    bytes: null,
+    custom: null,
+    types: null,
+};
+
+writeEnvelope(valid, pbf);
+
+// @ts-expect-error
+writeEnvelope(invalid, pbf);
diff --git a/test/typescript/package.json b/test/typescript/package.json
new file mode 100644
index 0000000..07aaeb6
--- /dev/null
+++ b/test/typescript/package.json
@@ -0,0 +1,14 @@
+{
+  "name": "pbf-ts",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "tsc": "tsc --project tsconfig.json"
+  },
+  "dependencies": {
+    "pbf": "file:../../"
+  },
+  "devDependencies": {
+    "typescript": "^5.5.3"
+  }
+}
diff --git a/test/typescript/tsconfig.json b/test/typescript/tsconfig.json
new file mode 100644
index 0000000..3d7c1d0
--- /dev/null
+++ b/test/typescript/tsconfig.json
@@ -0,0 +1,10 @@
+{
+  "compilerOptions": {
+    "allowJs": true,
+    "module": "nodenext",
+    "moduleResolution": "nodenext",
+    "noEmit": true,
+    "strict": true,
+    "target": "esnext",
+  }
+}