How to add items to page list using javascript

Question

I want to add pages on pages list, when btnAddPage is clicked opens a dialog with two inputs, addPageTitle and addPageTags but I don't know how to create those pages. I've already created Items to a custom list I've made and I've tried using the same function but it didn't work. Does anyone know how to add those two fields on a new item on pages list?

Update:

I've made some research and manage to find this code:

function createFile(resultpanel) {
   var clientContext;
   var oWebsite;
   var oList;
   var fileCreateInfo;
   var fileContent;

   clientContext = new SP.ClientContext.get_current();
   oWebsite = clientContext.get_web();
   oList = oWebsite.get_lists().getByTitle("Pages");

   fileCreateInfo = new SP.FileCreationInformation();
   fileCreateInfo.set_url("title.aspx");
   fileCreateInfo.set_content(new SP.Base64EncodedByteArray());
   fileContent = "The content of my new file";

   for (var i = 0; i < fileContent.length; i++) {

       fileCreateInfo.get_content().append(fileContent.charCodeAt(i));
   }

   this.newFile = oList.get_rootFolder().get_files().add(fileCreateInfo);

   clientContext.load(this.newFile);
   clientContext.executeQueryAsync(
       Function.createDelegate(this, successHandler),
       Function.createDelegate(this, errorHandler)
  );

function successHandler() {
    resultpanel.innerHTML =
        "Go to the " +
        "<a href='../Pages'>document library</a> " +
        "to see your new file.";
}

function errorHandler() {
    resultpanel.innerHTML = "Request failed: " + arguments[1].get_message();
}
}

That works perfectly but still can't add anything to a field Tags.

Update 2:

The answer below indeed adds a page but a blank one, the whole document(site) is blank. So I went through Rest Api check what was wrong and found that was missing some attribute:

<d:PublishingPageLayout m:type="SP.FieldUrlValue">
  <d:Description>Basic Page</d:Description>
<d:Url>http://deliveryoffice.telecom.pt/_catalogs/masterpage/EnterpriseWiki.aspx</d:Url> 
</d:PublishingPageLayout>

Does anyone knows how to add this?

Answer 1

Use set_item to set the associated field data for the page item and create with a page layout in master page Gallery like below:

 <script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jquery/1.8.1/jquery.min.js"></script>  
<script type="text/javascript">  
    $(document).ready(function() {  
        var scriptbase = _spPageContextInfo.webAbsoluteUrl+ "/_layouts/15/";  
          $.getScript(scriptbase + "SP.Runtime.js", function() {  
            $.getScript(scriptbase + "SP.js", function() {  
                $.getScript(scriptbase + "SP.Publishing.js", createPublishingPage);  
            });  
        });          
    });  
    var oWeb, clientContext, pageLayoutitem;  

    function createPublishingPage() {  
        //Get the client context,web and list object(Master Page Gallery)   
        clientContext = new SP.ClientContext.get_current();  
        oWeb = clientContext.get_web();  
        var oList = oWeb.get_lists().getByTitle('Master Page Gallery');  
        //Get the page layout by ID using which we will create a publishing page   
        pageLayoutitem = oList.getItemById(7);  
        //Load the client context and execute the batch   
        clientContext.load(oWeb);  
        clientContext.load(pageLayoutitem);  
        clientContext.executeQueryAsync(QuerySuccess, QueryFailure);  
    }  

    function QuerySuccess() {  
        //Create Publishing Page using PublishingPageInformation object   
        var newPublishingPage = SP.Publishing.PublishingWeb.getPublishingWeb(clientContext, oWeb);  
        var pageInfo = new SP.Publishing.PublishingPageInformation();  
        pageInfo.set_name("New Publishing Page.aspx");  
        pageInfo.set_pageLayoutListItem(pageLayoutitem);  
        newPage = newPublishingPage.addPublishingPage(pageInfo);
        console.log(newPage);
         var wikipage = newPage.get_listItem();
         console.log(wikipage);
           wikipage.set_item("Title","test");
           wikipage.set_item("tags","testtag");
           wikipage.update();
           clientContext.load(newPage);  
           clientContext.load(wikipage);
        clientContext.executeQueryAsync(SecondQuerySuccess, SecondQueryFailure);  
    }  

    function QueryFailure(sender, args) {  
        console.log('Request failed' + args.get_message());  
    }  

    function SecondQuerySuccess(sender, args) {  
        console.log("Publishing page created successfully.");  
    }  

    function SecondQueryFailure(sender, args) {  
        console.log('Request failed' + args.get_message());  
    }  
</script>

This is the page layout in Master Page Gallery and the id is 7

This is the result, it will create a publishing page based on the default layout:

Reference Demo from here:

Create A Publishing Page In SharePoint Using Javascript Object Model