diff --git a/.babelrc b/.babelrc
index 29a1161..fa3808b 100644
--- a/.babelrc
+++ b/.babelrc
@@ -1,13 +1,16 @@
 {
 	"presets": [
-		[ "@babel/env", {
-			"modules": false
-		} ],
-		"@babel/preset-typescript"
+		"@babel/preset-typescript",
+		[
+			"@babel/env",
+			{
+				"modules": false
+			}
+		]
 	],
 	"env": {
 		"test": {
-			"presets": [ "@babel/env" ]
+			"presets": ["@babel/preset-typescript", "@babel/env"]
 		}
 	}
 }
diff --git a/.eslintrc.json b/.eslintrc.json
index f9da10c..ebd81cd 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -1,20 +1,12 @@
 {
-	"root": true,
-	"extends": ["eslint:recommended", "prettier", "plugin:@typescript-eslint/recommended"],
-	"plugins": ["prettier"],
-	"parser": "@typescript-eslint/parser",
-	"parserOptions": {
-		"ecmaVersion": 2020,
-		"sourceType": "module",
-		"project": ["./tsconfig.json", "./tsconfig.eslint.json"]
-	},
+	"extends": "@aduth/eslint-config",
 	"env": {
-		"es6": true,
 		"browser": true,
 		"mocha": true,
 		"node": true
 	},
 	"rules": {
-		"prettier/prettier": "error"
+		"no-redeclare": "off",
+		"@typescript-eslint/no-redeclare": "error"
 	}
 }
diff --git a/.gitignore b/.gitignore
index 9d27333..3d5ae6a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,4 @@
 /es/*
-!/es/index.d.ts
 node_modules/
 *.log
 dist/
diff --git a/mocha-setup.js b/mocha-setup.js
new file mode 100644
index 0000000..f437bb5
--- /dev/null
+++ b/mocha-setup.js
@@ -0,0 +1,3 @@
+import register from '@babel/register';
+
+register({ extensions: ['.ts'] });
diff --git a/package-lock.json b/package-lock.json
index a246c19..3cf2fa8 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,6 +9,7 @@
       "version": "1.3.0",
       "license": "MIT",
       "devDependencies": {
+        "@aduth/eslint-config": "^4.4.1",
         "@babel/cli": "^7.20.7",
         "@babel/core": "^7.20.12",
         "@babel/preset-env": "^7.20.2",
@@ -17,19 +18,67 @@
         "@rollup/plugin-babel": "^6.0.3",
         "@rollup/plugin-node-resolve": "^15.0.1",
         "@rollup/plugin-terser": "^0.4.0",
-        "@typescript-eslint/eslint-plugin": "^5.53.0",
-        "@typescript-eslint/parser": "^5.53.0",
+        "@types/chai": "^4.3.4",
+        "@types/mocha": "^10.0.1",
+        "@typescript-eslint/eslint-plugin": "^5.55.0",
+        "@typescript-eslint/parser": "^5.55.0",
         "chai": "^4.3.7",
         "eslint": "^8.34.0",
-        "eslint-config-prettier": "^8.6.0",
+        "eslint-config-prettier": "^8.7.0",
         "eslint-plugin-prettier": "^4.2.1",
         "jsdom": "^21.1.0",
+        "jsdom-global": "^3.0.2",
         "mocha": "^10.2.0",
         "prettier": "^2.8.4",
         "rollup": "^3.15.0",
         "typescript": "^5.0.2"
       }
     },
+    "node_modules/@aduth/eslint-config": {
+      "version": "4.4.1",
+      "resolved": "https://registry.npmjs.org/@aduth/eslint-config/-/eslint-config-4.4.1.tgz",
+      "integrity": "sha512-0DzJLhVxFtdBv8ONS1jgz/gbKDHBzv+piev07pSi5sgnMepxBGbFgRZeASVGyWo9njIQE6ExnCIvemittg44Lw==",
+      "dev": true,
+      "dependencies": {
+        "@aduth/is-dependency": "^1.0.0",
+        "deepmerge": "^4.2.2"
+      },
+      "peerDependencies": {
+        "@typescript-eslint/eslint-plugin": ">=4.27.0",
+        "@typescript-eslint/parser": ">=4.27.0",
+        "eslint": ">=7.28.0",
+        "eslint-config-prettier": ">=8.3.0",
+        "eslint-plugin-jsdoc": ">=35.3.0",
+        "eslint-plugin-prettier": ">=3.4.0",
+        "typescript": ">=4.3.4"
+      },
+      "peerDependenciesMeta": {
+        "@typescript-eslint/eslint-plugin": {
+          "optional": true
+        },
+        "@typescript-eslint/parser": {
+          "optional": true
+        },
+        "eslint-config-prettier": {
+          "optional": true
+        },
+        "eslint-plugin-jsdoc": {
+          "optional": true
+        },
+        "eslint-plugin-prettier": {
+          "optional": true
+        },
+        "typescript": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/@aduth/is-dependency": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/@aduth/is-dependency/-/is-dependency-1.0.0.tgz",
+      "integrity": "sha512-1CJwTd6B6XDb6HETcHMwjRmQLQi2FgjM1rYUO6wf1yizKVPC9V66vmvVCtgePMzWmhsLqdhOPLWt+fNvG46FoA==",
+      "dev": true
+    },
     "node_modules/@ampproject/remapping": {
       "version": "2.2.0",
       "resolved": "https://registry.npmjs.org/@ampproject/remapping/-/remapping-2.2.0.tgz",
@@ -1777,6 +1826,30 @@
         "node": ">=6.9.0"
       }
     },
+    "node_modules/@eslint-community/eslint-utils": {
+      "version": "4.3.0",
+      "resolved": "https://registry.npmjs.org/@eslint-community/eslint-utils/-/eslint-utils-4.3.0.tgz",
+      "integrity": "sha512-v3oplH6FYCULtFuCeqyuTd9D2WKO937Dxdq+GmHOLL72TTRriLxz2VLlNfkZRsvj6PKnOPAtuT6dwrs/pA5DvA==",
+      "dev": true,
+      "dependencies": {
+        "eslint-visitor-keys": "^3.3.0"
+      },
+      "engines": {
+        "node": "^12.22.0 || ^14.17.0 || >=16.0.0"
+      },
+      "peerDependencies": {
+        "eslint": "^6.0.0 || ^7.0.0 || >=8.0.0"
+      }
+    },
+    "node_modules/@eslint-community/regexpp": {
+      "version": "4.4.0",
+      "resolved": "https://registry.npmjs.org/@eslint-community/regexpp/-/regexpp-4.4.0.tgz",
+      "integrity": "sha512-A9983Q0LnDGdLPjxyXQ00sbV+K+O+ko2Dr+CZigbHWtX9pNfxlaBkMR8X1CztI73zuEyEBXTVjx7CE+/VSwDiQ==",
+      "dev": true,
+      "engines": {
+        "node": "^12.0.0 || ^14.0.0 || >=16.0.0"
+      }
+    },
     "node_modules/@eslint/eslintrc": {
       "version": "1.4.1",
       "resolved": "https://registry.npmjs.org/@eslint/eslintrc/-/eslintrc-1.4.1.tgz",
@@ -2065,6 +2138,12 @@
         "node": ">= 10"
       }
     },
+    "node_modules/@types/chai": {
+      "version": "4.3.4",
+      "resolved": "https://registry.npmjs.org/@types/chai/-/chai-4.3.4.tgz",
+      "integrity": "sha512-KnRanxnpfpjUTqTCXslZSEdLfXExwgNxYPdiO2WGUj8+HDjFi8R3k5RVKPeSCzLjCcshCAtVO2QBbVuAV4kTnw==",
+      "dev": true
+    },
     "node_modules/@types/estree": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/@types/estree/-/estree-1.0.0.tgz",
@@ -2077,6 +2156,12 @@
       "integrity": "sha512-wOuvG1SN4Us4rez+tylwwwCV1psiNVOkJeM3AUWUNWg/jDQY2+HE/444y5gc+jBmRqASOm2Oeh5c1axHobwRKQ==",
       "dev": true
     },
+    "node_modules/@types/mocha": {
+      "version": "10.0.1",
+      "resolved": "https://registry.npmjs.org/@types/mocha/-/mocha-10.0.1.tgz",
+      "integrity": "sha512-/fvYntiO1GeICvqbQ3doGDIP97vWmvFt83GKguJ6prmQM2iXZfFcq6YE8KteFyRtX2/h5Hf91BYvPodJKFYv5Q==",
+      "dev": true
+    },
     "node_modules/@types/resolve": {
       "version": "1.20.2",
       "resolved": "https://registry.npmjs.org/@types/resolve/-/resolve-1.20.2.tgz",
@@ -2090,19 +2175,19 @@
       "dev": true
     },
     "node_modules/@typescript-eslint/eslint-plugin": {
-      "version": "5.54.1",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-5.54.1.tgz",
-      "integrity": "sha512-a2RQAkosH3d3ZIV08s3DcL/mcGc2M/UC528VkPULFxR9VnVPT8pBu0IyBAJJmVsCmhVfwQX1v6q+QGnmSe1bew==",
+      "version": "5.55.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-5.55.0.tgz",
+      "integrity": "sha512-IZGc50rtbjk+xp5YQoJvmMPmJEYoC53SiKPXyqWfv15XoD2Y5Kju6zN0DwlmaGJp1Iw33JsWJcQ7nw0lGCGjVg==",
       "dev": true,
       "dependencies": {
-        "@typescript-eslint/scope-manager": "5.54.1",
-        "@typescript-eslint/type-utils": "5.54.1",
-        "@typescript-eslint/utils": "5.54.1",
+        "@eslint-community/regexpp": "^4.4.0",
+        "@typescript-eslint/scope-manager": "5.55.0",
+        "@typescript-eslint/type-utils": "5.55.0",
+        "@typescript-eslint/utils": "5.55.0",
         "debug": "^4.3.4",
         "grapheme-splitter": "^1.0.4",
         "ignore": "^5.2.0",
         "natural-compare-lite": "^1.4.0",
-        "regexpp": "^3.2.0",
         "semver": "^7.3.7",
         "tsutils": "^3.21.0"
       },
@@ -2157,14 +2242,14 @@
       "dev": true
     },
     "node_modules/@typescript-eslint/parser": {
-      "version": "5.54.1",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/parser/-/parser-5.54.1.tgz",
-      "integrity": "sha512-8zaIXJp/nG9Ff9vQNh7TI+C3nA6q6iIsGJ4B4L6MhZ7mHnTMR4YP5vp2xydmFXIy8rpyIVbNAG44871LMt6ujg==",
+      "version": "5.55.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/parser/-/parser-5.55.0.tgz",
+      "integrity": "sha512-ppvmeF7hvdhUUZWSd2EEWfzcFkjJzgNQzVST22nzg958CR+sphy8A6K7LXQZd6V75m1VKjp+J4g/PCEfSCmzhw==",
       "dev": true,
       "dependencies": {
-        "@typescript-eslint/scope-manager": "5.54.1",
-        "@typescript-eslint/types": "5.54.1",
-        "@typescript-eslint/typescript-estree": "5.54.1",
+        "@typescript-eslint/scope-manager": "5.55.0",
+        "@typescript-eslint/types": "5.55.0",
+        "@typescript-eslint/typescript-estree": "5.55.0",
         "debug": "^4.3.4"
       },
       "engines": {
@@ -2184,13 +2269,13 @@
       }
     },
     "node_modules/@typescript-eslint/scope-manager": {
-      "version": "5.54.1",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/scope-manager/-/scope-manager-5.54.1.tgz",
-      "integrity": "sha512-zWKuGliXxvuxyM71UA/EcPxaviw39dB2504LqAmFDjmkpO8qNLHcmzlh6pbHs1h/7YQ9bnsO8CCcYCSA8sykUg==",
+      "version": "5.55.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/scope-manager/-/scope-manager-5.55.0.tgz",
+      "integrity": "sha512-OK+cIO1ZGhJYNCL//a3ROpsd83psf4dUJ4j7pdNVzd5DmIk+ffkuUIX2vcZQbEW/IR41DYsfJTB19tpCboxQuw==",
       "dev": true,
       "dependencies": {
-        "@typescript-eslint/types": "5.54.1",
-        "@typescript-eslint/visitor-keys": "5.54.1"
+        "@typescript-eslint/types": "5.55.0",
+        "@typescript-eslint/visitor-keys": "5.55.0"
       },
       "engines": {
         "node": "^12.22.0 || ^14.17.0 || >=16.0.0"
@@ -2201,13 +2286,13 @@
       }
     },
     "node_modules/@typescript-eslint/type-utils": {
-      "version": "5.54.1",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/type-utils/-/type-utils-5.54.1.tgz",
-      "integrity": "sha512-WREHsTz0GqVYLIbzIZYbmUUr95DKEKIXZNH57W3s+4bVnuF1TKe2jH8ZNH8rO1CeMY3U4j4UQeqPNkHMiGem3g==",
+      "version": "5.55.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/type-utils/-/type-utils-5.55.0.tgz",
+      "integrity": "sha512-ObqxBgHIXj8rBNm0yh8oORFrICcJuZPZTqtAFh0oZQyr5DnAHZWfyw54RwpEEH+fD8suZaI0YxvWu5tYE/WswA==",
       "dev": true,
       "dependencies": {
-        "@typescript-eslint/typescript-estree": "5.54.1",
-        "@typescript-eslint/utils": "5.54.1",
+        "@typescript-eslint/typescript-estree": "5.55.0",
+        "@typescript-eslint/utils": "5.55.0",
         "debug": "^4.3.4",
         "tsutils": "^3.21.0"
       },
@@ -2228,9 +2313,9 @@
       }
     },
     "node_modules/@typescript-eslint/types": {
-      "version": "5.54.1",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/types/-/types-5.54.1.tgz",
-      "integrity": "sha512-G9+1vVazrfAfbtmCapJX8jRo2E4MDXxgm/IMOF4oGh3kq7XuK3JRkOg6y2Qu1VsTRmWETyTkWt1wxy7X7/yLkw==",
+      "version": "5.55.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/types/-/types-5.55.0.tgz",
+      "integrity": "sha512-M4iRh4AG1ChrOL6Y+mETEKGeDnT7Sparn6fhZ5LtVJF1909D5O4uqK+C5NPbLmpfZ0XIIxCdwzKiijpZUOvOug==",
       "dev": true,
       "engines": {
         "node": "^12.22.0 || ^14.17.0 || >=16.0.0"
@@ -2241,13 +2326,13 @@
       }
     },
     "node_modules/@typescript-eslint/typescript-estree": {
-      "version": "5.54.1",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/typescript-estree/-/typescript-estree-5.54.1.tgz",
-      "integrity": "sha512-bjK5t+S6ffHnVwA0qRPTZrxKSaFYocwFIkZx5k7pvWfsB1I57pO/0M0Skatzzw1sCkjJ83AfGTL0oFIFiDX3bg==",
+      "version": "5.55.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/typescript-estree/-/typescript-estree-5.55.0.tgz",
+      "integrity": "sha512-I7X4A9ovA8gdpWMpr7b1BN9eEbvlEtWhQvpxp/yogt48fy9Lj3iE3ild/1H3jKBBIYj5YYJmS2+9ystVhC7eaQ==",
       "dev": true,
       "dependencies": {
-        "@typescript-eslint/types": "5.54.1",
-        "@typescript-eslint/visitor-keys": "5.54.1",
+        "@typescript-eslint/types": "5.55.0",
+        "@typescript-eslint/visitor-keys": "5.55.0",
         "debug": "^4.3.4",
         "globby": "^11.1.0",
         "is-glob": "^4.0.3",
@@ -2301,18 +2386,18 @@
       "dev": true
     },
     "node_modules/@typescript-eslint/utils": {
-      "version": "5.54.1",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/utils/-/utils-5.54.1.tgz",
-      "integrity": "sha512-IY5dyQM8XD1zfDe5X8jegX6r2EVU5o/WJnLu/znLPWCBF7KNGC+adacXnt5jEYS9JixDcoccI6CvE4RCjHMzCQ==",
+      "version": "5.55.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/utils/-/utils-5.55.0.tgz",
+      "integrity": "sha512-FkW+i2pQKcpDC3AY6DU54yl8Lfl14FVGYDgBTyGKB75cCwV3KpkpTMFi9d9j2WAJ4271LR2HeC5SEWF/CZmmfw==",
       "dev": true,
       "dependencies": {
+        "@eslint-community/eslint-utils": "^4.2.0",
         "@types/json-schema": "^7.0.9",
         "@types/semver": "^7.3.12",
-        "@typescript-eslint/scope-manager": "5.54.1",
-        "@typescript-eslint/types": "5.54.1",
-        "@typescript-eslint/typescript-estree": "5.54.1",
+        "@typescript-eslint/scope-manager": "5.55.0",
+        "@typescript-eslint/types": "5.55.0",
+        "@typescript-eslint/typescript-estree": "5.55.0",
         "eslint-scope": "^5.1.1",
-        "eslint-utils": "^3.0.0",
         "semver": "^7.3.7"
       },
       "engines": {
@@ -2382,12 +2467,12 @@
       "dev": true
     },
     "node_modules/@typescript-eslint/visitor-keys": {
-      "version": "5.54.1",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/visitor-keys/-/visitor-keys-5.54.1.tgz",
-      "integrity": "sha512-q8iSoHTgwCfgcRJ2l2x+xCbu8nBlRAlsQ33k24Adj8eoVBE0f8dUeI+bAa8F84Mv05UGbAx57g2zrRsYIooqQg==",
+      "version": "5.55.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/visitor-keys/-/visitor-keys-5.55.0.tgz",
+      "integrity": "sha512-q2dlHHwWgirKh1D3acnuApXG+VNXpEY5/AwRxDVuEQpxWaB0jCDe0jFMVMALJ3ebSfuOVE8/rMS+9ZOYGg1GWw==",
       "dev": true,
       "dependencies": {
-        "@typescript-eslint/types": "5.54.1",
+        "@typescript-eslint/types": "5.55.0",
         "eslint-visitor-keys": "^3.3.0"
       },
       "engines": {
@@ -3166,9 +3251,9 @@
       }
     },
     "node_modules/eslint-config-prettier": {
-      "version": "8.6.0",
-      "resolved": "https://registry.npmjs.org/eslint-config-prettier/-/eslint-config-prettier-8.6.0.tgz",
-      "integrity": "sha512-bAF0eLpLVqP5oEVUFKpMA+NnRFICwn9X8B5jrR9FcqnYBuPbqWEjTEspPWMj5ye6czoSLDweCzSo3Ko7gGrZaA==",
+      "version": "8.7.0",
+      "resolved": "https://registry.npmjs.org/eslint-config-prettier/-/eslint-config-prettier-8.7.0.tgz",
+      "integrity": "sha512-HHVXLSlVUhMSmyW4ZzEuvjpwqamgmlfkutD53cYXLikh4pt/modINRcCIApJ84czDxM4GZInwUrromsDdTImTA==",
       "dev": true,
       "bin": {
         "eslint-config-prettier": "bin/cli.js"
@@ -4214,6 +4299,15 @@
         }
       }
     },
+    "node_modules/jsdom-global": {
+      "version": "3.0.2",
+      "resolved": "https://registry.npmjs.org/jsdom-global/-/jsdom-global-3.0.2.tgz",
+      "integrity": "sha512-t1KMcBkz/pT5JrvcJbpUR2u/w1kO9jXctaaGJ0vZDzwFnIvGWw9IDSRciT83kIs8Bnw4qpOl8bQK08V01YgMPg==",
+      "dev": true,
+      "peerDependencies": {
+        "jsdom": ">=10.0.0"
+      }
+    },
     "node_modules/jsesc": {
       "version": "2.5.2",
       "resolved": "https://registry.npmjs.org/jsesc/-/jsesc-2.5.2.tgz",
diff --git a/package.json b/package.json
index b04b804..6d64aeb 100644
--- a/package.json
+++ b/package.json
@@ -19,14 +19,15 @@
     "src"
   ],
   "scripts": {
-    "build:es": "babel src/ --extensions \".js,.ts,\" --out-dir es",
+    "build:es": "babel src/ --extensions '.ts' --out-dir es",
     "build:umd": "rollup -c",
-    "build:types": "tsc -b",
-    "build": "npm run build:es && npm run build:umd",
+    "build:types": "tsc -b tsconfig.decl.json",
+    "build": "npm run build:es && npm run build:umd && npm run build:types",
     "dev": "rollup -c -w",
     "lint": "eslint . --ignore-pattern dist --ignore-pattern es",
-    "unit-test": "NODE_ENV=test mocha --require @babel/register",
-    "test": "npm run unit-test && npm run lint",
+    "unit-test": "NODE_ENV=test mocha -r jsdom-global/register -r @babel/register -r ./mocha-setup.js --extension ts",
+    "typecheck": "tsc",
+    "test": "npm run unit-test && npm run lint && npm run typecheck",
     "prepublishOnly": "npm run build"
   },
   "author": {
@@ -36,6 +37,7 @@
   },
   "license": "MIT",
   "devDependencies": {
+    "@aduth/eslint-config": "^4.4.1",
     "@babel/cli": "^7.20.7",
     "@babel/core": "^7.20.12",
     "@babel/preset-env": "^7.20.2",
@@ -44,13 +46,16 @@
     "@rollup/plugin-babel": "^6.0.3",
     "@rollup/plugin-node-resolve": "^15.0.1",
     "@rollup/plugin-terser": "^0.4.0",
-    "@typescript-eslint/eslint-plugin": "^5.53.0",
-    "@typescript-eslint/parser": "^5.53.0",
+    "@types/chai": "^4.3.4",
+    "@types/mocha": "^10.0.1",
+    "@typescript-eslint/eslint-plugin": "^5.55.0",
+    "@typescript-eslint/parser": "^5.55.0",
     "chai": "^4.3.7",
     "eslint": "^8.34.0",
-    "eslint-config-prettier": "^8.6.0",
+    "eslint-config-prettier": "^8.7.0",
     "eslint-plugin-prettier": "^4.2.1",
     "jsdom": "^21.1.0",
+    "jsdom-global": "^3.0.2",
     "mocha": "^10.2.0",
     "prettier": "^2.8.4",
     "rollup": "^3.15.0",
diff --git a/rollup.config.mjs b/rollup.config.mjs
index 6efbef9..27f14fa 100644
--- a/rollup.config.mjs
+++ b/rollup.config.mjs
@@ -12,10 +12,10 @@ export default [
 		},
 		plugins: [
 			nodeResolve({
-				extensions: ['.js', '.ts'],
+				extensions: ['.ts'],
 			}),
 			babel({
-				extensions: ['.js', '.ts'],
+				extensions: ['.ts'],
 				babelHelpers: 'bundled',
 				exclude: 'node_modules/**',
 				presets: ['@babel/preset-typescript'],
@@ -31,10 +31,10 @@ export default [
 		},
 		plugins: [
 			nodeResolve({
-				extensions: ['.js', '.ts'],
+				extensions: ['.ts'],
 			}),
 			babel({
-				extensions: ['.js', '.ts'],
+				extensions: ['.ts'],
 				babelHelpers: 'bundled',
 				exclude: 'node_modules/**',
 				presets: ['@babel/preset-typescript'],
diff --git a/src/index.ts b/src/index.ts
index 87a0d9a..cc443fb 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -3,9 +3,17 @@
  */
 import getPath from './get-path';
 
-type MatcherFn<T = any> = (node: Element) => T | undefined;
-type MatcherObj<T = any> = { [key: string]: MatcherFn<T> | MatcherObj<T> };
-type Matcher<T = any> = MatcherFn<T> | MatcherObj<T>;
+export type MatcherFn<T = any> = (node: Element) => T | undefined;
+
+export type MatcherObj = { [key: string]: MatcherFn | MatcherObj };
+
+export type MatcherObjResult<F extends MatcherFn, O extends MatcherObj> = {
+	[K in keyof O]: O[K] extends F
+		? ReturnType<O[K]>
+		: O[K] extends MatcherObj
+		? MatcherObjResult<F, O[K]>
+		: never;
+};
 
 /**
  * Function returning a DOM document created by `createHTMLDocument`. The same
@@ -28,21 +36,56 @@ const getDocument = (() => {
  * Given a markup string or DOM element, creates an object aligning with the
  * shape of the matchers object, or the value returned by the matcher.
  *
- * @param source   Source content
+ * @param source Source content
  * @param matchers Matcher function or object of matchers
- * @return         Matched value(s), shaped by object
  */
-export function parse<F extends MatcherFn<any>, O extends MatcherObj<F> = {}>(
-	source: Element | string,
+export function parse(source: string | Element, matchers?: undefined): undefined;
+
+/**
+ * Given a markup string or DOM element, creates an object aligning with the
+ * shape of the matchers object, or the value returned by the matcher.
+ *
+ * @param source Source content
+ * @param matchers Object of matchers
+ * @return Matched values, shaped by object
+ */
+export function parse<F extends MatcherFn, O extends MatcherObj>(
+	source: string | Element,
 	matchers: O
-): { [K in keyof O]: O[K] extends F ? ReturnType<O[K]> : O[K] };
-export function parse<F extends MatcherFn<any>>(
-	source: Element | string,
-	matchers: F
-): ReturnType<F>;
-export function parse<F extends MatcherFn<any>, O extends MatcherObj<F> = {}>(
-	source: Element | string,
+): MatcherObjResult<F, O>;
+
+/**
+ * Given a markup string or DOM element, creates an object aligning with the
+ * shape of the matchers object, or the value returned by the matcher.
+ *
+ * @param source Source content
+ * @param matcher Matcher function
+ * @return Matched value
+ */
+export function parse<F extends MatcherFn>(source: string | Element, matchers: F): ReturnType<F>;
+
+/**
+ * Given a markup string or DOM element, creates an object aligning with the
+ * shape of the matchers object, or the value returned by the matcher.
+ *
+ * @param source Source content
+ * @param matchers Matcher function or object of matchers
+ */
+export function parse<F extends MatcherFn, O extends MatcherObj>(
+	source: string | Element,
 	matchers: O | F
+): MatcherObjResult<F, O> | ReturnType<F>;
+
+/**
+ * Given a markup string or DOM element, creates an object aligning with the
+ * shape of the matchers object, or the value returned by the matcher.
+ *
+ * @param source Source content
+ * @param matchers Matcher function or object of matchers
+ */
+export function parse<F extends MatcherFn, O extends MatcherObj>(
+	source: string | Element,
+	matchers?: O | F
 ) {
 	if (!matchers) {
 		return;
@@ -56,7 +99,7 @@ export function parse<F extends MatcherFn<any>, O extends MatcherObj<F> = {}>(
 	}
 
 	// Return singular value
-	if ('function' === typeof matchers) {
+	if (typeof matchers === 'function') {
 		return matchers(source);
 	}
 
@@ -66,24 +109,50 @@ export function parse<F extends MatcherFn<any>, O extends MatcherObj<F> = {}>(
 	}
 
 	// Shape result by matcher object
-	return Object.keys(matchers).reduce((memo, key) => {
-		memo[key] = parse(source, matchers[key] as MatcherObj<F>);
+	return Object.keys(matchers).reduce((memo, key: keyof MatcherObjResult<F, O>) => {
+		const inner = matchers[key];
+		memo[key] = parse(source, inner);
 		return memo;
-	}, {} as Record<string, any>);
+	}, {} as MatcherObjResult<F, O>);
 }
 
+/**
+ * Generates a function which matches node of type selector, returning an
+ * attribute by property if the attribute exists. If no selector is passed,
+ * returns property of the query element.
+ *
+ * @param name Property name
+ * @return Property value
+ */
+export function prop<N extends keyof Element>(name: string): MatcherFn<Element[N]>;
+
+/**
+ * Generates a function which matches node of type selector, returning an
+ * attribute by property if the attribute exists. If no selector is passed,
+ * returns property of the query element.
+ *
+ * @param selector Optional selector
+ * @param name Property name
+ * @return Property value
+ */
+export function prop<N extends keyof Element>(
+	selector: string | undefined,
+	name: N
+): MatcherFn<Element[N]>;
+
 /**
  * Generates a function which matches node of type selector, returning an
  * attribute by property if the attribute exists. If no selector is passed,
  * returns property of the query element.
  *
  * @param selector Optional selector
- * @param name     Property name
- * @return         Property value
+ * @param name Property name
+ * @return Property value
  */
-export function prop<T = any>(name: string): MatcherFn<T>;
-export function prop<T = any>(selector: string | undefined, name: string): MatcherFn<T>;
-export function prop<T = any>(arg1: string | undefined, arg2?: string): MatcherFn<T> {
+export function prop<N extends keyof Element>(
+	arg1: string | undefined,
+	arg2?: string
+): MatcherFn<Element[N]> {
 	let name: string;
 	let selector: string | undefined;
 	if (1 === arguments.length) {
@@ -93,29 +162,48 @@ export function prop<T = any>(arg1: string | undefined, arg2?: string): MatcherF
 		name = arg2 as string;
 		selector = arg1;
 	}
-	return function (node: Element) {
+	return function (node: Element): Element[N] | undefined {
 		let match: Element | null = node;
 		if (selector) {
 			match = node.querySelector(selector);
 		}
 		if (match) {
-			return getPath(match, name) as T;
+			return getPath(match, name) as Element[N] | undefined;
 		}
-	};
+	} as MatcherFn<Element[N]>;
 }
 
+/**
+ * Generates a function which matches node of type selector, returning an
+ * attribute by name if the attribute exists. If no selector is passed,
+ * returns attribute of the query element.
+ *
+ * @param name Attribute name
+ * @return Attribute value
+ */
+export function attr(name: string): MatcherFn<string>;
+
 /**
  * Generates a function which matches node of type selector, returning an
  * attribute by name if the attribute exists. If no selector is passed,
  * returns attribute of the query element.
  *
  * @param selector Optional selector
- * @param name     Attribute name
- * @return         Attribute value
+ * @param name Attribute name
+ * @return Attribute value
  */
-export function attr<T = any>(name: string): MatcherFn<T>;
-export function attr<T = any>(selector: string | undefined, name: string): MatcherFn<T>;
-export function attr<T = any>(arg1: string | undefined, arg2?: string): MatcherFn<T> {
+export function attr(selector: string | undefined, name: string): MatcherFn<string>;
+
+/**
+ * Generates a function which matches node of type selector, returning an
+ * attribute by name if the attribute exists. If no selector is passed,
+ * returns attribute of the query element.
+ *
+ * @param selector Optional selector
+ * @param name Attribute name
+ * @return Attribute value
+ */
+export function attr(arg1: string | undefined, arg2?: string): MatcherFn<string> {
 	let name: string;
 	let selector: string | undefined;
 	if (1 === arguments.length) {
@@ -125,10 +213,10 @@ export function attr<T = any>(arg1: string | undefined, arg2?: string): MatcherF
 		name = arg2 as string;
 		selector = arg1;
 	}
-	return function (node: Element): T | undefined {
-		const attributes = prop(selector, 'attributes')(node);
+	return function (node: Element): string | undefined {
+		const attributes = prop(selector, 'attributes')(node) as NamedNodeMap | undefined;
 		if (attributes && Object.prototype.hasOwnProperty.call(attributes, name)) {
-			return attributes[name].value;
+			return attributes[name as any].value;
 		}
 	};
 }
@@ -139,10 +227,10 @@ export function attr<T = any>(arg1: string | undefined, arg2?: string): MatcherF
  * @see prop()
  *
  * @param selector Optional selector
- * @return         Inner HTML
+ * @return Inner HTML
  */
-export function html<T = any>(selector?: string) {
-	return prop<T>(selector, 'innerHTML');
+export function html(selector?: string) {
+	return prop(selector, 'innerHTML') as MatcherFn<string>;
 }
 
 /**
@@ -150,11 +238,11 @@ export function html<T = any>(selector?: string) {
  *
  * @see prop()
  *
- * @param  selector Optional selector
- * @return          Text content
+ * @param selector Optional selector
+ * @return Text content
  */
-export function text<T = any>(selector?: string) {
-	return prop<T>(selector, 'textContent');
+export function text(selector?: string) {
+	return prop(selector, 'textContent') as MatcherFn<string>;
 }
 
 /**
@@ -166,11 +254,14 @@ export function text<T = any>(selector?: string) {
  *
  * @param selector Selector to match
  * @param matchers Matcher function or object of matchers
- * @return         Matcher function which returns an array of matched value(s)
+ * @return Matcher function which returns an array of matched value(s)
  */
-export function query<T = any>(selector: string, matchers: Matcher<T>) {
-	return function (node: Element): any[] {
+export function query<F extends MatcherFn, O extends MatcherObj>(
+	selector: string,
+	matchers?: F | O
+) {
+	return function (node: Element) {
 		const matches = node.querySelectorAll(selector);
-		return [].map.call(matches, (match) => parse<MatcherFn<T>>(match, matchers));
+		return [].map.call(matches, (match) => parse(match, matchers!)) as MatcherObjResult<F, O>[];
 	};
 }
diff --git a/test/get-path.js b/test/get-path.ts
similarity index 100%
rename from test/get-path.js
rename to test/get-path.ts
diff --git a/test/index.js b/test/index.ts
similarity index 89%
rename from test/index.js
rename to test/index.ts
index 17d585a..cefeb7d 100644
--- a/test/index.js
+++ b/test/index.ts
@@ -14,23 +14,12 @@ describe('hpq', () => {
 		'<blockquote><p>…</p><p>…</p><cite class="large"><em>—</em> Andrew</cite></blockquote>';
 
 	// Element
-	let element;
+	let element: HTMLElement;
 
 	before(() => {
-		const { JSDOM } = require('jsdom');
-		global.window = new JSDOM('').window;
-		global.document = window.document;
-		global.navigator = window.navigator;
-
 		element = document.createElement('div');
 		element.innerHTML = markup;
-		element = element.firstChild;
-	});
-
-	after(() => {
-		delete global.document;
-		delete global.window;
-		delete global.navigator;
+		element = element.firstChild as HTMLElement;
 	});
 
 	describe('parse()', () => {
@@ -52,7 +41,8 @@ describe('hpq', () => {
 			expect(result).to.equal('— Andrew');
 		});
 
-		it('should return undefiend if passed matchers other than object, function', () => {
+		it('should return undefined if passed matchers other than object, function', () => {
+			// @ts-ignore
 			const result = parse(element, 2);
 
 			expect(result).to.be.undefined;
@@ -71,6 +61,7 @@ describe('hpq', () => {
 
 	describe('prop()', () => {
 		it('should return a matcher function', () => {
+			// @ts-ignore
 			const matcher = prop();
 
 			expect(matcher).to.be.a('function');
@@ -103,6 +94,7 @@ describe('hpq', () => {
 
 	describe('attr()', () => {
 		it('should return a matcher function', () => {
+			// @ts-ignore
 			const matcher = attr();
 
 			expect(matcher).to.be.a('function');
@@ -180,12 +172,6 @@ describe('hpq', () => {
 	});
 
 	describe('query()', () => {
-		it('should return a matcher function', () => {
-			const matcher = query();
-
-			expect(matcher).to.be.a('function');
-		});
-
 		it('should return array of parse on matched nodes', () => {
 			const result = parse(element, { text: query('p', text()) });
 
diff --git a/tsconfig.decl.json b/tsconfig.decl.json
new file mode 100644
index 0000000..7e6747b
--- /dev/null
+++ b/tsconfig.decl.json
@@ -0,0 +1,11 @@
+{
+	"extends": "./tsconfig.json",
+	"compilerOptions": {
+		"declaration": true,
+		"emitDeclarationOnly": true,
+		"outDir": "./es",
+		"rootDir": "src",
+		"noEmit": false
+	},
+	"include": ["src"]
+}
diff --git a/tsconfig.eslint.json b/tsconfig.eslint.json
deleted file mode 100644
index ff08772..0000000
--- a/tsconfig.eslint.json
+++ /dev/null
@@ -1,7 +0,0 @@
-{
-  "extends": "./tsconfig",
-  "compilerOptions": {
-    "noEmit": true
-  },
-  "include": ["**/*.js"]
-}
diff --git a/tsconfig.json b/tsconfig.json
index bf631e0..e9c4b06 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,13 +1,10 @@
 {
-  "compilerOptions": {
-    "target": "ES2017",
-    "lib": ["ES2017", "DOM", "DOM.Iterable"],
-    "outDir": "./es",
-    "strict": true,
-    "allowJs": true,
-    "checkJs": true,
-    "declaration": true,
-    "emitDeclarationOnly": true
-  },
-  "include": ["src/**/*.js"]
+	"compilerOptions": {
+		"target": "ES2017",
+		"lib": ["ES2017", "DOM", "DOM.Iterable"],
+		"moduleResolution": "node",
+		"strict": true,
+		"noEmit": true
+	},
+	"include": ["src", "test"]
 }