Typescript code added

main.ts

@@ -0,0 +1,158 @@
+enum Roles {
+  USER = "user",
+  ADMIN = "admin",
+}
+enum HttpMethods {
+  HTTP_GET_METHOD = "GET",
+  HTTP_POST_METHOD = "POST",
+}
+enum HttpStatus {
+  HTTP_STATUS_OK = 200,
+  HTTP_STATUS_INTERNAL_SERVER_ERROR = 500,
+}
+interface UserMockModelType {
+  name: string;
+  age: number;
+  roles: Roles[];
+  createdAt: Date;
+  isDeleated: boolean;
+}
+interface RequestMockType {
+  method: HttpMethods;
+  host: string;
+  path: string;
+  body?: UserMockModelType;
+  params?: {
+    [key: string]: string;
+  };
+}
+interface HandlersType {
+  next: (value: RequestMockType) => void;
+  error: (error?: string) => void;
+  complete: () => void;
+}
+class Observer {
+  public _unsubscribe: () => void;
+  private isUnsubscribed: boolean;
+  private handlers: HandlersType;
+  constructor(handlers: HandlersType) {
+    this.handlers = handlers;
+    this.isUnsubscribed = false;
+  }
+
+  next(value: RequestMockType) {
+    if (this.handlers.next && !this.isUnsubscribed) {
+      this.handlers.next(value);
+    }
+  }
+
+  error(error?: string) {
+    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 {
+  private _subscribe;
+  constructor(subscribe) {
+    this._subscribe = subscribe;
+  }
+
+  static from(values: RequestMockType[]) {
+    return new Observable((observer: Observer) => {
+      values.forEach((value) => observer.next(value));
+
+      observer.complete();
+
+      return () => {
+        console.log("unsubscribed");
+      };
+    });
+  }
+
+  subscribe(obs: HandlersType) {
+    const observer = new Observer(obs);
+
+    observer._unsubscribe = this._subscribe(observer);
+
+    return {
+      unsubscribe() {
+        observer.unsubscribe();
+      },
+    };
+  }
+}
+
+const userMock: UserMockModelType = {
+  name: "User Name",
+  age: 26,
+  roles: [Roles.USER, Roles.ADMIN],
+  createdAt: new Date(),
+  isDeleated: false,
+};
+
+const requestsMock: RequestMockType[] = [
+  {
+    method: HttpMethods.HTTP_GET_METHOD,
+    host: "service.example",
+    path: "user",
+    body: userMock,
+    params: {},
+  },
+  {
+    method: HttpMethods.HTTP_POST_METHOD,
+    host: "service.example",
+    path: "user",
+    params: {
+      id: "3f5h67s4s",
+    },
+  },
+];
+
+const handleRequest: (request: RequestMockType) => {
+  status: HttpStatus;
+} = (request: RequestMockType) => {
+  // handling of request
+  return { status: HttpStatus.HTTP_STATUS_OK };
+};
+const handleError: (error?: string) => {
+  status: HttpStatus;
+} = (error) => {
+  // handling of error
+  return { status: HttpStatus.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();