add index.d.ts

package.json

@@ -13,7 +13,7 @@
     "snaptests": "TAP_SNAPSHOT=1 npm test",
     "pretest": "npm run lint && npm run build",
     "test": "tap test/*.spec.js --reporter spec --coverage",
-    "build": "ncc -s -m build src/index.js ",
+    "build": "ncc -s -m build src/index.js && cp src/*.d.ts dist",
     "prepublishOnly": "npm run build"
   },
   "devDependencies": {

src/index.d.ts

@@ -0,0 +1,12 @@
+interface BadgenOptions {
+  status: string;
+  subject?: string;
+  color?: string;
+  style?: StyleOption;
+  icon?: string;
+  iconWidth?: 13;
+}
+
+type StyleOption = 'flat' | 'classic'
+
+export default function badgen(options: BadgenOptions): string;