Add types

package.json

@@ -95,5 +95,6 @@
   "lint-staged": {
     "src/**/*.js": "eslint",
     "test/**/*.js": "eslint"
-  }
+  },
+  "types": "./src/index.d.ts"
 }

src/index.d.ts

@@ -0,0 +1,38 @@
+// to avoid mistakenly treating d.ts as js by ESLint.
+/* eslint-disable */
+declare class Kuroshiro {
+  constructor();
+  init(_analyzer: any): Promise<void>;
+  convert(
+    str: string,
+    options?: {
+      to?: string;
+      mode?: string;
+      romajiSystem?: string;
+      delimiter_start?: string;
+      delimiter_end?: string;
+    }
+  ): Promise<string>;
+  Util: {
+    isHiragana: (ch: string) => boolean;
+    isKatakana: (ch: string) => boolean;
+    isKana: (ch: string) => boolean;
+    isKanji: (ch: string) => boolean;
+    isJapanese: (ch: string) => boolean;
+    hasHiragana: (str: string) => boolean;
+    hasKatakana: (str: string) => boolean;
+    hasKana: (str: string) => boolean;
+    hasKanji: (str: string) => boolean;
+    hasJapanese: (str: string) => boolean;
+    kanaToHiragana: (str: string) => string;
+    kanaToKatakana: (str: string) => string;
+    kanaToRomaji: (
+      str: string,
+      system: "nippon" | "passport" | "hepburn"
+    ) => string;
+  };
+}
+
+declare module "kuroshiro" {
+  export = Kuroshiro;
+}