diff --git a/.eslintrc.json b/.eslintrc.json
index d187d17c..c72280b9 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -1,4 +1,6 @@
 {
   "root": true,
-  "extends": "hexo"
+  "parser": "@typescript-eslint/parser",
+  "plugins": ["@typescript-eslint"],
+  "extends": ["hexo"]
 }
diff --git a/.gitignore b/.gitignore
index 62df31e9..60768cde 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,4 +4,5 @@ node_modules/
 .nyc_output/
 *.log
 docs/
-coverage/
\ No newline at end of file
+coverage/
+built
\ No newline at end of file
diff --git a/.tsconfig.json b/.tsconfig.json
new file mode 100644
index 00000000..b50946d5
--- /dev/null
+++ b/.tsconfig.json
@@ -0,0 +1,10 @@
+{
+    "compilerOptions": {
+        "outDir": "./lib",
+        "allowJs": true,
+        "target": "ES2018"
+    },
+    "include": [
+        "./src/**/*"
+    ]
+}
\ No newline at end of file
diff --git a/package.json b/package.json
index 992efb9b..f8acc884 100644
--- a/package.json
+++ b/package.json
@@ -2,18 +2,21 @@
   "name": "warehouse",
   "version": "4.0.0",
   "description": "Simple JSON-based database",
-  "main": "lib/database",
+  "main": "built/database",
   "directories": {
-    "lib": "./lib"
+    "lib": "./built"
   },
   "files": [
-    "lib/"
+    "built/"
   ],
   "scripts": {
-    "eslint": "eslint lib test",
+    "pretest": "npm run typescript",
+    "typescript": "tsc --build .tsconfig.json",
+    "eslint": "eslint src test",
     "test": "mocha \"test/scripts/**/*.js\"",
     "test-cov": "nyc --reporter=lcov --reporter=text-summary npm test",
-    "jsdoc": "jsdoc --configure .jsdoc.json"
+    "jsdoc": "jsdoc --configure .jsdoc.json",
+    "prepublish": "npm run typescript"
   },
   "repository": "hexojs/warehouse",
   "keywords": [
@@ -32,6 +35,8 @@
     "rfdc": "^1.1.4"
   },
   "devDependencies": {
+    "@typescript-eslint/eslint-plugin": "^3.0.0",
+    "@typescript-eslint/parser": "^3.0.0",
     "chai": "^4.2.0",
     "chai-as-promised": "^7.1.1",
     "eslint": "^7.0.0",
@@ -41,7 +46,8 @@
     "minami": "^1.1.1",
     "mocha": "^7.0.0",
     "nyc": "^15.0.0",
-    "sinon": "^9.0.2"
+    "sinon": "^9.0.2",
+    "typescript": "^3.9.3"
   },
   "engines": {
     "node": ">=10.13.0"
diff --git a/lib/database.js b/src/database.js
similarity index 100%
rename from lib/database.js
rename to src/database.js
diff --git a/lib/document.js b/src/document.js
similarity index 100%
rename from lib/document.js
rename to src/document.js
diff --git a/lib/error.js b/src/error.js
similarity index 100%
rename from lib/error.js
rename to src/error.js
diff --git a/lib/error/population.js b/src/error/population.js
similarity index 100%
rename from lib/error/population.js
rename to src/error/population.js
diff --git a/lib/error/validation.js b/src/error/validation.js
similarity index 100%
rename from lib/error/validation.js
rename to src/error/validation.js
diff --git a/lib/model.js b/src/model.js
similarity index 100%
rename from lib/model.js
rename to src/model.js
diff --git a/lib/mutex.js b/src/mutex.js
similarity index 100%
rename from lib/mutex.js
rename to src/mutex.js
diff --git a/lib/query.js b/src/query.js
similarity index 100%
rename from lib/query.js
rename to src/query.js
diff --git a/lib/schema.js b/src/schema.js
similarity index 100%
rename from lib/schema.js
rename to src/schema.js
diff --git a/lib/schematype.js b/src/schematype.js
similarity index 100%
rename from lib/schematype.js
rename to src/schematype.js
diff --git a/lib/types/array.js b/src/types/array.js
similarity index 100%
rename from lib/types/array.js
rename to src/types/array.js
diff --git a/lib/types/boolean.js b/src/types/boolean.js
similarity index 100%
rename from lib/types/boolean.js
rename to src/types/boolean.js
diff --git a/lib/types/buffer.js b/src/types/buffer.js
similarity index 100%
rename from lib/types/buffer.js
rename to src/types/buffer.js
diff --git a/lib/types/cuid.js b/src/types/cuid.js
similarity index 100%
rename from lib/types/cuid.js
rename to src/types/cuid.js
diff --git a/lib/types/date.js b/src/types/date.js
similarity index 100%
rename from lib/types/date.js
rename to src/types/date.js
diff --git a/lib/types/enum.js b/src/types/enum.js
similarity index 100%
rename from lib/types/enum.js
rename to src/types/enum.js
diff --git a/lib/types/index.js b/src/types/index.js
similarity index 100%
rename from lib/types/index.js
rename to src/types/index.js
diff --git a/lib/types/integer.js b/src/types/integer.js
similarity index 100%
rename from lib/types/integer.js
rename to src/types/integer.js
diff --git a/lib/types/number.js b/src/types/number.js
similarity index 100%
rename from lib/types/number.js
rename to src/types/number.js
diff --git a/lib/types/object.js b/src/types/object.js
similarity index 100%
rename from lib/types/object.js
rename to src/types/object.js
diff --git a/lib/types/string.js b/src/types/string.js
similarity index 100%
rename from lib/types/string.js
rename to src/types/string.js
diff --git a/lib/types/virtual.js b/src/types/virtual.js
similarity index 100%
rename from lib/types/virtual.js
rename to src/types/virtual.js
diff --git a/lib/util.js b/src/util.js
similarity index 100%
rename from lib/util.js
rename to src/util.js
diff --git a/test/fixtures/db.json b/test/fixtures/db.json
index 5a796455..32e13d6e 100644
--- a/test/fixtures/db.json
+++ b/test/fixtures/db.json
@@ -1 +1 @@
-{"meta":{"version":1,"warehouse":"3.0.1"},"models":{"Test":[{"_id":"A"},{"_id":"B"},{"_id":"C"}]}}
\ No newline at end of file
+{"meta":{"version":1,"warehouse":"4.0.0"},"models":{"Test":[{"_id":"A"},{"_id":"B"},{"_id":"C"}]}}
\ No newline at end of file
diff --git a/test/scripts/database.js b/test/scripts/database.js
index 30001e87..a7b518a5 100644
--- a/test/scripts/database.js
+++ b/test/scripts/database.js
@@ -10,8 +10,8 @@ const DB_PATH = path.join(path.dirname(__dirname), 'fixtures', 'db.json');
 const DB_VERSION = 1;
 
 describe('Database', () => {
-  const Database = require('../..');
-  const Model = require('../../lib/model');
+  const Database = require('../../built/database');
+  const Model = require('../../built/model');
   const Schema = Database.Schema;
   const db = new Database({path: DB_PATH, version: DB_VERSION});
 
diff --git a/test/scripts/document.js b/test/scripts/document.js
index ba9d359c..0a7f680d 100644
--- a/test/scripts/document.js
+++ b/test/scripts/document.js
@@ -4,7 +4,7 @@ const should = require('chai').should(); // eslint-disable-line
 
 describe('Document', () => {
   const Database = require('../..');
-  const Document = require('../../lib/document');
+  const Document = require('../../built/document');
   const db = new Database();
   const Schema = Database.Schema;
 
diff --git a/test/scripts/mutex.js b/test/scripts/mutex.js
index 4df3c5af..cf8b1e19 100644
--- a/test/scripts/mutex.js
+++ b/test/scripts/mutex.js
@@ -1,7 +1,7 @@
 'use strict';
 
 const should = require('chai').should(); // eslint-disable-line
-const Mutex = require('../../lib/mutex');
+const Mutex = require('../../built/mutex');
 const sinon = require('sinon');
 
 describe('Mutex', () => {
diff --git a/test/scripts/query.js b/test/scripts/query.js
index 06a99af6..3af8f565 100644
--- a/test/scripts/query.js
+++ b/test/scripts/query.js
@@ -3,7 +3,7 @@
 const should = require('chai').should(); // eslint-disable-line
 const sortBy = require('lodash/sortBy');
 const Promise = require('bluebird');
-const Document = require('../../lib/document');
+const Document = require('../../built/document');
 
 describe('Query', () => {
   const Database = require('../..');
diff --git a/test/scripts/schematype.js b/test/scripts/schematype.js
index 6ed1bf25..b086d00a 100644
--- a/test/scripts/schematype.js
+++ b/test/scripts/schematype.js
@@ -1,10 +1,10 @@
 'use strict';
 
 const should = require('chai').should(); // eslint-disable-line
-const ValidationError = require('../../lib/error/validation');
+const ValidationError = require('../../built/error/validation');
 
 describe('SchemaType', () => {
-  const SchemaType = require('../../lib/schematype');
+  const SchemaType = require('../../built/schematype');
   const type = new SchemaType('test');
 
   it('cast()', () => {
diff --git a/test/scripts/types/array.js b/test/scripts/types/array.js
index 7228343d..2f08cb3a 100644
--- a/test/scripts/types/array.js
+++ b/test/scripts/types/array.js
@@ -1,13 +1,13 @@
 'use strict';
 
 const should = require('chai').should(); // eslint-disable-line
-const ValidationError = require('../../../lib/error/validation');
+const ValidationError = require('../../../built/error/validation');
 
 describe('SchemaTypeArray', () => {
-  const SchemaTypeArray = require('../../../lib/types/array');
-  const SchemaTypeString = require('../../../lib/types/string');
-  const SchemaTypeDate = require('../../../lib/types/date');
-  const SchemaTypeBoolean = require('../../../lib/types/boolean');
+  const SchemaTypeArray = require('../../../built/types/array');
+  const SchemaTypeString = require('../../../built/types/string');
+  const SchemaTypeDate = require('../../../built/types/date');
+  const SchemaTypeBoolean = require('../../../built/types/boolean');
   const type = new SchemaTypeArray('test');
 
   it('cast()', () => {
diff --git a/test/scripts/types/boolean.js b/test/scripts/types/boolean.js
index 07be269f..2a51dae2 100644
--- a/test/scripts/types/boolean.js
+++ b/test/scripts/types/boolean.js
@@ -1,10 +1,10 @@
 'use strict';
 
 require('chai').should();
-const ValidationError = require('../../../lib/error/validation');
+const ValidationError = require('../../../built/error/validation');
 
 describe('SchemaTypeBoolean', () => {
-  const SchemaTypeBoolean = require('../../../lib/types/boolean');
+  const SchemaTypeBoolean = require('../../../built/types/boolean');
   const type = new SchemaTypeBoolean('test');
 
   it('cast()', () => {
diff --git a/test/scripts/types/buffer.js b/test/scripts/types/buffer.js
index 3c6c62d9..7263b5b0 100644
--- a/test/scripts/types/buffer.js
+++ b/test/scripts/types/buffer.js
@@ -1,10 +1,10 @@
 'use strict';
 
 const should = require('chai').should();
-const ValidationError = require('../../../lib/error/validation');
+const ValidationError = require('../../../built/error/validation');
 
 describe('SchemaTypeBuffer', () => {
-  const SchemaTypeBuffer = require('../../../lib/types/buffer');
+  const SchemaTypeBuffer = require('../../../built/types/buffer');
   const type = new SchemaTypeBuffer('test');
 
   it('cast()', () => {
diff --git a/test/scripts/types/cuid.js b/test/scripts/types/cuid.js
index f17cd89c..c70830f8 100644
--- a/test/scripts/types/cuid.js
+++ b/test/scripts/types/cuid.js
@@ -1,10 +1,10 @@
 'use strict';
 
 const should = require('chai').should(); // eslint-disable-line
-const ValidationError = require('../../../lib/error/validation');
+const ValidationError = require('../../../built/error/validation');
 
 describe('SchemaTypeCUID', () => {
-  const SchemaTypeCUID = require('../../../lib/types/cuid');
+  const SchemaTypeCUID = require('../../../built/types/cuid');
   const type = new SchemaTypeCUID('test');
 
   it('cast()', () => {
diff --git a/test/scripts/types/date.js b/test/scripts/types/date.js
index 912bec84..b366398d 100644
--- a/test/scripts/types/date.js
+++ b/test/scripts/types/date.js
@@ -1,10 +1,10 @@
 'use strict';
 
 const should = require('chai').should(); // eslint-disable-line
-const ValidationError = require('../../../lib/error/validation');
+const ValidationError = require('../../../built/error/validation');
 
 describe('SchemaTypeDate', () => {
-  const SchemaTypeDate = require('../../../lib/types/date');
+  const SchemaTypeDate = require('../../../built/types/date');
   const type = new SchemaTypeDate('test');
 
   it('cast()', () => {
diff --git a/test/scripts/types/enum.js b/test/scripts/types/enum.js
index 166c3888..94522209 100644
--- a/test/scripts/types/enum.js
+++ b/test/scripts/types/enum.js
@@ -1,10 +1,10 @@
 'use strict';
 
 require('chai').should();
-const ValidationError = require('../../../lib/error/validation');
+const ValidationError = require('../../../built/error/validation');
 
 describe('SchemaTypeEnum', () => {
-  const SchemaTypeEnum = require('../../../lib/types/enum');
+  const SchemaTypeEnum = require('../../../built/types/enum');
 
   it('validate()', () => {
     const type = new SchemaTypeEnum('test', {elements: ['foo', 'bar', 'baz']});
diff --git a/test/scripts/types/integer.js b/test/scripts/types/integer.js
index 9589fad1..60f22d80 100644
--- a/test/scripts/types/integer.js
+++ b/test/scripts/types/integer.js
@@ -1,10 +1,10 @@
 'use strict';
 
 require('chai').should();
-const ValidationError = require('../../../lib/error/validation');
+const ValidationError = require('../../../built/error/validation');
 
 describe('SchemaTypeInteger', () => {
-  const SchemaTypeInteger = require('../../../lib/types/integer');
+  const SchemaTypeInteger = require('../../../built/types/integer');
   const type = new SchemaTypeInteger('test');
 
   it('cast()', () => {
diff --git a/test/scripts/types/number.js b/test/scripts/types/number.js
index 6442196e..107b1f64 100644
--- a/test/scripts/types/number.js
+++ b/test/scripts/types/number.js
@@ -1,10 +1,10 @@
 'use strict';
 
 require('chai').should();
-const ValidationError = require('../../../lib/error/validation');
+const ValidationError = require('../../../built/error/validation');
 
 describe('SchemaTypeNumber', () => {
-  const SchemaTypeNumber = require('../../../lib/types/number');
+  const SchemaTypeNumber = require('../../../built/types/number');
   const type = new SchemaTypeNumber('type');
 
   it('cast()', () => {
diff --git a/test/scripts/types/object.js b/test/scripts/types/object.js
index a5cd9c74..d6ef04e0 100644
--- a/test/scripts/types/object.js
+++ b/test/scripts/types/object.js
@@ -3,7 +3,7 @@
 const should = require('chai').should(); // eslint-disable-line
 
 describe('SchemaTypeObject', () => {
-  const SchemaTypeObject = require('../../../lib/types/object');
+  const SchemaTypeObject = require('../../../built/types/object');
   const type = new SchemaTypeObject('test');
 
   it('cast() - default', () => {
diff --git a/test/scripts/types/string.js b/test/scripts/types/string.js
index 2425d012..cbb601f1 100644
--- a/test/scripts/types/string.js
+++ b/test/scripts/types/string.js
@@ -1,10 +1,10 @@
 'use strict';
 
 require('chai').should();
-const ValidationError = require('../../../lib/error/validation');
+const ValidationError = require('../../../built/error/validation');
 
 describe('SchemaTypeString', () => {
-  const SchemaTypeString = require('../../../lib/types/string');
+  const SchemaTypeString = require('../../../built/types/string');
   const type = new SchemaTypeString('test');
 
   it('cast()', () => {
diff --git a/test/scripts/types/virtual.js b/test/scripts/types/virtual.js
index 515cbbcb..23671158 100644
--- a/test/scripts/types/virtual.js
+++ b/test/scripts/types/virtual.js
@@ -3,7 +3,7 @@
 const should = require('chai').should(); // eslint-disable-line
 
 describe('SchemaTypeVirtual', () => {
-  const SchemaTypeVirtual = require('../../../lib/types/virtual');
+  const SchemaTypeVirtual = require('../../../built/types/virtual');
   const type = new SchemaTypeVirtual('test');
 
   it('get()', () => {
diff --git a/test/scripts/util.js b/test/scripts/util.js
index 5a23df2a..9a67c0e2 100644
--- a/test/scripts/util.js
+++ b/test/scripts/util.js
@@ -3,7 +3,7 @@
 const should = require('chai').should(); // eslint-disable-line
 
 describe('util', () => {
-  const util = require('../../lib/util');
+  const util = require('../../built/util');
 
   it('shuffle()', () => {
     const src = Array(100).fill(0).map((_, i) => i);