From ca8e2373aadd25a4ccddb1a167dde9f2fb6345e6 Mon Sep 17 00:00:00 2001
From: Jenny Gallegos <dev.jenny.ga@gmail.com>
Date: Mon, 2 Feb 2026 20:19:55 -0600
Subject: [PATCH] Refactor: convert to TS and add types

---
 index.js | 127 ---------------------------------------
 index.ts | 178 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 178 insertions(+), 127 deletions(-)
 delete mode 100644 index.js
 create mode 100644 index.ts

diff --git a/index.js b/index.js
deleted file mode 100644
index c0f3ec3..0000000
--- a/index.js
+++ /dev/null
@@ -1,127 +0,0 @@
-class Observer {
-  constructor(handlers) {
-    this.handlers = handlers;
-    this.isUnsubscribed = false;
-  }
-
-  next(value) {
-    if (this.handlers.next && !this.isUnsubscribed) {
-      this.handlers.next(value);
-    }
-  }
-
-  error(error) {
-    if (!this.isUnsubscribed) {
-      if (this.handlers.error) {
-        this.handlers.error(error);
-      }
-
-      this.unsubscribe();
-    }
-  }
-
-  complete() {
-    if (!this.isUnsubscribed) {
-      if (this.handlers.complete) {
-        this.handlers.complete();
-      }
-
-      this.unsubscribe();
-    }
-  }
-
-  unsubscribe() {
-    this.isUnsubscribed = true;
-
-    if (this._unsubscribe) {
-      this._unsubscribe();
-    }
-  }
-}
-
-class Observable {
-  constructor(subscribe) {
-    this._subscribe = subscribe;
-  }
-
-  static from(values) {
-    return new Observable((observer) => {
-      values.forEach((value) => observer.next(value));
-
-      observer.complete();
-
-      return () => {
-        console.log('unsubscribed');
-      };
-    });
-  }
-
-  subscribe(obs) {
-    const observer = new Observer(obs);
-
-    observer._unsubscribe = this._subscribe(observer);
-
-    return ({
-      unsubscribe() {
-        observer.unsubscribe();
-      }
-    });
-  }
-}
-
-const HTTP_POST_METHOD = 'POST';
-const HTTP_GET_METHOD = 'GET';
-
-const HTTP_STATUS_OK = 200;
-const HTTP_STATUS_INTERNAL_SERVER_ERROR = 500;
-
-
-const userMock = {
-  name: 'User Name',
-  age: 26,
-  roles: [
-    'user',
-    'admin'
-  ],
-  createdAt: new Date(),
-  isDeleated: false,
-};
-
-const requestsMock = [
-  {
-    method: HTTP_POST_METHOD,
-    host: 'service.example',
-    path: 'user',
-    body: userMock,
-    params: {},
-  },
-  {
-    method: HTTP_GET_METHOD,
-    host: 'service.example',
-    path: 'user',
-    params: {
-      id: '3f5h67s4s'
-    },
-  }
-];
-
-const handleRequest = (request) => {
-  // handling of request
-  return {status: HTTP_STATUS_OK};
-};
-const handleError = (error) => {
-  // handling of error
-  return {status: HTTP_STATUS_INTERNAL_SERVER_ERROR};
-};
-
-const handleComplete = () => console.log('complete');
-
-const requests$ = Observable.from(requestsMock);
-
-const subscription = requests$.subscribe({
-  next: handleRequest,
-  error: handleError,
-  complete: handleComplete
-});
-
-subscription.unsubscribe();
diff --git a/index.ts b/index.ts
new file mode 100644
index 0000000..692017b
--- /dev/null
+++ b/index.ts
@@ -0,0 +1,178 @@
+enum HttpMethod {
+  POST = 'POST', 
+  GET = 'GET',
+  PUT = 'PUT',
+  DELETE = 'DELETE',
+  PATCH = 'PATCH'
+};
+
+enum HttpStatus {
+  Ok = 200,
+  InternalServerError = 500
+};
+
+type UserType = 'admin' | 'user';
+
+interface User {
+  name: string;
+  age: number;
+  roles: UserType[];
+  createdAt: Date;
+  isDeleted: boolean;
+};
+
+interface MyRequest {
+  method: string;
+  host: string;
+  path: string;
+  body?: User;
+  params: {
+    id?: string;
+  },
+}
+
+interface Result {
+  status: number;
+}
+
+type TeardownFunc = () => void;
+type SubscribeFunc<T> = (observer: Observer<T>) => TeardownFunc;
+
+interface ObserverHandlers<T> {
+  next?: (value: T) => void;
+  error?: (error: Error) => void;
+  complete?: () => void;
+}
+
+interface Subscription {
+  unsubscribe(): void;
+}
+
+class Observer<T> {
+  private handlers: ObserverHandlers<T>;
+  private isUnsubscribed: boolean;
+  public _unsubscribe?: TeardownFunc;
+
+  constructor(handlers: ObserverHandlers<T>) {
+    this.handlers = handlers;
+    this.isUnsubscribed = false;
+  }
+
+  next(value: T): void {
+    if (this.handlers.next && !this.isUnsubscribed) {
+      this.handlers.next(value);
+    }
+  }
+
+  error(error: Error): void {
+    if (!this.isUnsubscribed) {
+      if (this.handlers.error) {
+        this.handlers.error(error);
+      }
+
+      this.unsubscribe();
+    }
+  }
+
+  complete(): void {
+    if (!this.isUnsubscribed) {
+      if (this.handlers.complete) {
+        this.handlers.complete();
+      }
+
+      this.unsubscribe();
+    }
+  }
+
+  unsubscribe(): void {
+    this.isUnsubscribed = true;
+
+    if (this._unsubscribe) {
+      this._unsubscribe();
+    }
+  }
+}
+
+class Observable<T> {
+  private _subscribe: SubscribeFunc<T>;
+
+  constructor(subscribe: SubscribeFunc<T>) {
+    this._subscribe = subscribe;
+  }
+
+  static from<T>(values: T[]): Observable<T> {
+    return new Observable<T>((observer: Observer<T>) => {
+      values.forEach((value) => observer.next(value));
+
+      observer.complete();
+
+      return () => {
+        console.log('unsubscribed');
+      };
+    });
+  }
+
+  subscribe(obs: ObserverHandlers<T>): Subscription {
+    const observer = new Observer<T>(obs);
+
+    observer._unsubscribe = this._subscribe(observer);
+
+    return ({
+      unsubscribe(): void {
+        observer.unsubscribe();
+      }
+    });
+  }
+}
+
+
+
+const userMock: User = {
+  name: 'User Name',
+  age: 26,
+  roles: [
+    'user',
+    'admin'
+  ],
+  createdAt: new Date(),
+  isDeleted: false,
+};
+
+const requestsMock: MyRequest[] = [
+  {
+    method: HttpMethod.POST,
+    host: 'service.example',
+    path: 'user',
+    body: userMock,
+    params: {},
+  },
+  {
+    method: HttpMethod.GET,
+    host: 'service.example',
+    path: 'user',
+    params: {
+      id: '3f5h67s4s'
+    },
+  }
+];
+
+const handleRequest = (request: MyRequest): Result => {
+  // handling of request
+  return {status: HttpStatus.Ok};
+};
+const handleError = (error: Error): Result => {
+  // handling of error
+  return {status: HttpStatus.InternalServerError};
+};
+
+const handleComplete = (): void => console.log('complete');
+
+const requests$: Observable<MyRequest> = Observable.from(requestsMock);
+
+const subscription = requests$.subscribe({
+  next: handleRequest,
+  error: handleError,
+  complete: handleComplete
+});
+
+subscription.unsubscribe();