diff --git a/.eslintignore b/.eslintignore
index 0a00463..399f374 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -1,4 +1,2 @@
 dist
-__test__
-node_modules
-website
\ No newline at end of file
+node_modules
\ No newline at end of file
diff --git a/__test__/hello.test.js b/__test__/hello.test.js
deleted file mode 100644
index 467ca8d..0000000
--- a/__test__/hello.test.js
+++ /dev/null
@@ -1,6 +0,0 @@
-import { test, expect } from "vitest";
-import { sayHello } from "../src";
-
-test("hello world", () => {
-  expect(sayHello()).toBe("Hello World");
-});
diff --git a/__test__/hello.test.ts b/__test__/hello.test.ts
new file mode 100644
index 0000000..20a1f50
--- /dev/null
+++ b/__test__/hello.test.ts
@@ -0,0 +1,41 @@
+import { describe } from "vitest";
+import { test, expect } from "vitest";
+import miis from "../src";
+
+describe("basic useage", () => {
+  test("subscribe", async () => {
+    await new Promise((resolve) => {
+      miis.subscribe("a", resolve);
+      miis.dispatch("a");
+    });
+  });
+
+  test("unsubscribe", async () => {
+    await new Promise((resolve, reject) => {
+      const unsubscribe = miis.subscribe("b", reject);
+      unsubscribe();
+      miis.dispatch("b");
+      setTimeout(resolve, 10);
+    });
+  });
+});
+
+describe("arguments", () => {
+  test("single", async () => {
+    const result = await new Promise((resolve) => {
+      miis.subscribe("b", resolve);
+      miis.dispatch("b", 1);
+    });
+    expect(result).toBe(1);
+  });
+
+  test("multi", async () => {
+    const result = await new Promise((resolve) => {
+      miis.subscribe("b", (...args) => {
+        resolve(Array.from(args));
+      });
+      miis.dispatch("b", 2, 3, 4);
+    });
+    expect(result).toEqual([2, 3, 4]);
+  });
+});
diff --git a/package.json b/package.json
index c2eb43b..f70c36c 100644
--- a/package.json
+++ b/package.json
@@ -1,22 +1,23 @@
 {
   "name": "miis",
   "version": "0.0.1",
-  "description": "Simple Start Template",
+  "description": "Tiny functional event subscriber and dispatcher.",
   "main": "index.ts",
   "scripts": {
     "build": "rollup -c rollup.config.js",
     "lint": "npx eslint src/**",
-    "prettier": "npx prettier src/** --write",
+    "prettier": "npx prettier src/** --write && npx prettier __test__/** --write",
     "test": "npx vitest",
     "test:run": "npx vitest run",
     "test:coverrage": "npx vitest --coverage",
     "publish": "npm run build && npm publish"
   },
   "keywords": [
-    "vite",
-    "vitest",
-    "docusaurus",
-    "template"
+    "event",
+    "emitter",
+    "subscribe",
+    "dispatch",
+    "linstener"
   ],
   "author": "Yukiniro",
   "license": "MIT",
@@ -44,5 +45,8 @@
     "tslib": "^2.3.1",
     "typescript": "^4.6.4",
     "vitest": "^0.12.2"
+  },
+  "dependencies": {
+    "bittydash": "^0.1.1"
   }
 }
\ No newline at end of file
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 0702bbc..3b05b65 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -10,6 +10,7 @@ specifiers:
   '@rollup/plugin-node-resolve': ^13.3.0
   '@rollup/plugin-typescript': ^8.3.1
   '@yukiniro/eslint-config': ^0.0.3
+  bittydash: ^0.1.1
   eslint: ^8.11.0
   prettier: ^2.6.0
   prettier-eslint: ^13.0.0
@@ -21,6 +22,9 @@ specifiers:
   typescript: ^4.6.4
   vitest: ^0.12.2
 
+dependencies:
+  bittydash: 0.1.1
+
 devDependencies:
   '@babel/core': 7.17.8
   '@babel/plugin-transform-modules-commonjs': 7.17.7_@babel+core@7.17.8
@@ -1832,6 +1836,10 @@ packages:
       tweetnacl: 0.14.5
     dev: true
 
+  /bittydash/0.1.1:
+    resolution: {integrity: sha512-ZfMy9OJB0Aeo183YclzIhxvCeA3D9aVj5gE3STBg+sOsBzKkZmjXvIbvq8FHNvDRjcF7CcwF9yRnu5ylVd9MyQ==}
+    dev: false
+
   /boxen/5.1.2:
     resolution: {integrity: sha512-9gYgQKXx+1nP8mP7CzFyaUARhg7D3n1dF/FnErWmu9l6JvGpNUN278h0aSb+QjoiKSWG+iZ3uHrcqk0qrY9RQQ==}
     engines: {node: '>=10'}
diff --git a/src/index.ts b/src/index.ts
index ed8e3e9..7ff8280 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,3 +1,48 @@
-export const sayHello = function () {
-  return "Hello World";
-}
\ No newline at end of file
+import { remove } from "bittydash";
+
+type Listener = (...args: any[]) => void;
+type EventName = string | symbol;
+type Options = {
+  once: boolean;
+};
+type Subscriber = {
+  listener: Listener;
+  once: boolean;
+};
+
+const handlerMap = new Map();
+
+function subscribe(
+  key: EventName,
+  listener: Listener,
+  options?: Options
+): () => void {
+  if (!handlerMap.has(key)) {
+    handlerMap.set(key, []);
+  }
+  const list = handlerMap.get(key);
+  const { once } = options || {};
+  const item = { listener, once };
+  list.push(item);
+  return () => {
+    remove(list, item);
+  };
+}
+
+function dispatch(key: EventName, ...args: any[]) {
+  const list = handlerMap.get(key) || [];
+  const removeList = [];
+  list.forEach((item: Subscriber) => {
+    const { listener, once } = item;
+    listener(...args);
+    if (once) {
+      removeList.push(item);
+    }
+  });
+  removeList.forEach((item: Subscriber) => remove(list, item));
+}
+
+export default {
+  subscribe,
+  dispatch,
+};