Setup Typescript, ignores and compiler options

.gitignore

@@ -1,2 +1,5 @@
 node_modules
 yarn.lock
+
+index.js
+index.d.ts

.npmignore

@@ -0,0 +1 @@
+index.ts

package.json

@@ -16,10 +16,13 @@
     "node": ">=4"
   },
   "scripts": {
-    "test": "xo && ava"
+    "test": "xo && ava",
+    "build": "tsc",
+    "prepublish": "tsc"    
   },
   "files": [
-    "index.js"
+    "index.js",
+    "index.d.ts"
   ],
   "keywords": [
     "type",
@@ -43,8 +46,10 @@
     "compare"
   ],
   "devDependencies": {
+    "@types/node": "^8.0.47",
     "ava": "*",
     "jsdom": "^9.12.0",
+    "typescript": "^2.6.1",
     "xo": "*"
   }
 }

tsconfig.json

@@ -0,0 +1,19 @@
+{
+    "compileOnSave": true,
+    "compilerOptions": {
+        "target": "es6",
+        "moduleResolution": "node",
+        "strict": true,
+        "alwaysStrict": true,
+        "declaration": true,
+        "outDir": ".",
+        "noImplicitAny": true,
+        "suppressImplicitAnyIndexErrors": true
+    },
+    "include": [
+        "index.ts"
+    ],
+    "exclude": [
+        "node_modules"
+    ]
+}