move EventEmitter to EventEmitter.ts and add tests

.vscode/settings.json

@@ -0,0 +1,6 @@
+{
+    "deno.enable": true,
+    "deno.lint": true,
+    "deno.unstable": true,
+    "deno.config": "../deno.jsonc"
+}

EventEmitter.test.ts

@@ -0,0 +1,122 @@
+import type { CustomEventMap, TypedCustomEvent } from "./EventEmitter.ts";
+import {
+    assertEquals,
+    assertThrows,
+    fail,
+} from "https://deno.land/std@0.92.0/testing/asserts.ts";
+
+import { EventEmitter } from "./EventEmitter.ts";
+
+interface Events extends CustomEventMap {
+    ping: TypedCustomEvent<"ping", undefined>;
+    pong: TypedCustomEvent<"pong", string>;
+    peng: TypedCustomEvent<"peng", { data: string }>;
+}
+
+Deno.test("types of detail", () => {
+    const emitter = new EventEmitter<Events>();
+
+    emitter.on("ping", (event) => {
+        assertEquals(event.detail, undefined);
+    });
+
+    emitter.emit("ping");
+
+    emitter.on("pong", (event) => {
+        assertEquals(event.detail, "hello");
+    });
+
+    emitter.emit("pong", "hello");
+
+    emitter.on("peng", (event) => {
+        assertEquals(event.detail.data, "peng emitted!")
+    });
+
+    emitter.emit("peng", {
+        data: "peng emitted!",
+    });
+});
+
+/**
+ * @see https://deno.land/x/event@2.0.0/test.ts
+ */
+
+Deno.test("on", () => {
+    const ee = new EventEmitter<Events>();
+
+    ee.on("foo", (event) => {
+        assertEquals(event.detail, "bar");
+    });
+
+    ee.emit("foo", "bar");
+});
+
+Deno.test("once", () => {
+    const ee = new EventEmitter<Events>();
+
+    ee.once("foo", (event) => {
+        assertEquals(event.detail, "bar");
+    });
+
+    ee.emit("foo", "bar");
+});
+
+Deno.test("off", () => {
+    const ee = new EventEmitter<Events>();
+
+    function foo() {
+        fail();
+    }
+
+    ee.on("foo", foo);
+
+    ee.off("foo", foo);
+
+    ee.emit("foo", "bar");
+});
+
+Deno.test("offEvent", () => {
+    const ee = new EventEmitter<Events>();
+
+    let i = 0;
+
+    ee.on("foo", () => i++);
+
+    ee.on("foo", () => i++);
+
+    ee.off();
+
+    ee.emit("foo", "bar");
+
+    assertEquals(i, 0);
+});
+
+Deno.test("offAll", () => {
+    const ee = new EventEmitter<Events>();
+
+    let i = 0;
+
+    ee.on("foo", () => i++);
+
+    ee.on("bar", () => i++);
+
+    ee.off();
+
+    ee.emit("foo", "bar");
+
+    assertEquals(i, 0);
+});
+
+Deno.test("chainable", () => {
+    const ee = new EventEmitter<Events>();
+
+    function foo() {
+        fail();
+    }
+
+    ee
+        .on("foo", foo)
+        .off("foo", foo);
+
+    ee.emit("foo", "bar");
+});