From ae83466cad42b43b5507b07f621faea87068024c Mon Sep 17 00:00:00 2001
From: Vitaliy Pasiuta <vpasiuta@griddynamics.com>
Date: Wed, 23 Aug 2023 18:00:08 +0300
Subject: [PATCH] init

---
 .gitignore        |   1 +
 index.js          |   3 +-
 package-lock.json |  12 ++++
 src/index.ts      | 158 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 173 insertions(+), 1 deletion(-)
 create mode 100644 .gitignore
 create mode 100644 package-lock.json
 create mode 100644 src/index.ts

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b512c09
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+node_modules
\ No newline at end of file
diff --git a/index.js b/index.js
index c0f3ec3..b6e255d 100644
--- a/index.js
+++ b/index.js
@@ -2,6 +2,7 @@ class Observer {
   constructor(handlers) {
     this.handlers = handlers;
     this.isUnsubscribed = false;
+    this._unsubscribe = undefined;
   }
 
   next(value) {
@@ -33,7 +34,7 @@ class Observer {
   unsubscribe() {
     this.isUnsubscribed = true;
 
-    if (this._unsubscribe) {
+if (this._unsubscribe) {
       this._unsubscribe();
     }
   }
diff --git a/package-lock.json b/package-lock.json
new file mode 100644
index 0000000..7f6fff6
--- /dev/null
+++ b/package-lock.json
@@ -0,0 +1,12 @@
+{
+  "requires": true,
+  "lockfileVersion": 1,
+  "dependencies": {
+    "typescript": {
+      "version": "5.1.6",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.1.6.tgz",
+      "integrity": "sha512-zaWCozRZ6DLEWAWFrVDz1H6FVXzUSfTy5FUMWsQlU8Ym5JP9eO4xkTIROFCQvhQf61z6O/G6ugw3SgAnvvm+HA==",
+      "dev": true
+    }
+  }
+}
diff --git a/src/index.ts b/src/index.ts
new file mode 100644
index 0000000..49817a1
--- /dev/null
+++ b/src/index.ts
@@ -0,0 +1,158 @@
+interface Handlers{
+  next: Function,
+  error:Function,
+  complete: Function,
+}
+
+interface User{
+  name: string,
+  age: number,
+  roles: string[],
+  createdAt: Date,
+  isDeleated: boolean,
+}
+
+class Observer {
+  handlers: Handlers;
+  isUnsubscribed: boolean;
+  _unsubscribe: Function;
+
+  constructor(handlers: Handlers) {
+    this.handlers = handlers;
+    this.isUnsubscribed = false;
+  }
+
+  next(value: Observer): void {
+    if (this.handlers.next && !this.isUnsubscribed) {
+      this.handlers.next(value);
+    }
+  }
+
+  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 {
+  _subscribe: Function;
+
+  constructor(subscribe) {
+    this._subscribe = subscribe;
+  }
+
+  static from(values) {
+    return new Observable((observer: Observer): Function => {
+      values.forEach((value) => observer.next(value));
+
+      observer.complete();
+
+      return (): void => {
+        console.log('unsubscribed');
+      };
+    });
+  }
+
+  subscribe(obs): Object {
+    const observer: Observer = new Observer(obs);
+
+    observer._unsubscribe = this._subscribe(observer);
+
+    return ({
+      unsubscribe() {
+        observer.unsubscribe();
+      }
+    });
+  }
+}
+
+type HTTP_METHODS = 'POST' | 'GET';
+type HTTP_STATUS = 200 | 500;
+
+const HTTP_POST_METHOD: HTTP_METHODS = 'POST';
+const HTTP_GET_METHOD: HTTP_METHODS = 'GET';
+
+const HTTP_STATUS_OK: HTTP_STATUS = 200;
+const HTTP_STATUS_INTERNAL_SERVER_ERROR: HTTP_STATUS = 500;
+
+
+const userMock: User = {
+  name: 'User Name',
+  age: 26,
+  roles: [
+    'user',
+    'admin'
+  ],
+  createdAt: new Date(),
+  isDeleated: false,
+};
+
+const requestsMock: {
+  method: HTTP_METHODS,
+  host: string,
+  path: string,
+  body?: object,
+  params: object,
+}[] = [
+  {
+    method: HTTP_POST_METHOD,
+    host: 'service.example',
+    path: 'user',
+    body: userMock,
+    params: {},
+  },
+  {
+    method: HTTP_GET_METHOD,
+    host: 'service.example',
+    path: 'user',
+    params: {
+      id: '3f5h67s4s'
+    },
+  }
+];
+
+type RESPONSE = {status: HTTP_STATUS};
+
+const handleRequest = (request): RESPONSE => {
+  // handling of request
+  return {status: HTTP_STATUS_OK};
+};
+const handleError = (error): RESPONSE => {
+  // handling of error
+  return {status: HTTP_STATUS_INTERNAL_SERVER_ERROR};
+};
+
+const handleComplete = (): void => console.log('complete');
+
+const requests$ = Observable.from(requestsMock);
+
+const subscription = requests$.subscribe({
+  next: handleRequest,
+  error: handleError,
+  complete: handleComplete
+});
+
+subscription.unsubscribe();