added implementations

src/pageObject.js

@@ -1,16 +1,38 @@
 'use strict';
 
 class Header {
-
-};
+  get logo() {
+    return 'Conduit logo';
+  }
+}
 
 class PageObject {
-
-};
+  constructor(url, header = new Header()) {
+    this.header = header;
+    this.url = url;
+  }
+  clickOnLogo() {
+    return 'Click on the ' + this.header.logo;
+  }
+}
 
 class ArticlePage extends PageObject {
+  constructor(url, slug) {
+    super();
+    this.url = url + slug;
+  }
+  get commentButton() {
+    return '[Publish comment] button';
+  }
 
-};
+  clickOnCommentButton() {
+    return 'Click on the ' + this.commentButton;
+  }
+
+  assertPageOpened() {
+    return 'The ' + this.url + ' is opened';
+  }
+}
 
 module.exports = {
   Header,