accessing and modifying page properties in sharepoint using javascript / CSOM / JSOM / Rest api

Question

I have a custom field "webPartId" in my page property

Whenever user clicks save, i want to update the field

I am not able to get any code snippets for that!

The closest i could reach is finding how to access the page properties via javascript / csom / REST api using below function

function getCurrentListItem(success, error)
{
   var context = SP.ClientContext.get_current();
   var web = context.get_web(); 
   var currentList = web.get_lists().getById(_spPageContextInfo.pageListId); 
   var currentListItem = currentList.getItemById(_spPageContextInfo.pageItemId);
   context.load(currentListItem);
   context.executeQueryAsync(
     function(){
        success(currentListItem);
     }, 
     error
   );
}
getCurrentListItem(
   function(listItem) {
       var webPartId= listItem.get_item('webPartId'); 
       console.log(webPartId);
   },
   function(sender,args){
        console.log(args.get_message());    
   }
);

Now i want to modify that property,

$("#saveWebPartId").click(function(){
//code to modify the page properties
});

Any client side snippet that can modify the page property is ok to me

Answer 1

I figured out the way for this

 listItem.set_item('FieldName',valueToBeSet); 
 listItem.update(); 
 var context = SP.ClientContext.get_current();
 context.executeQueryAsync(Function.createDelegate(this,this.onQuerySucceeded), 
       Function.createDelegate(this, this.onQueryFailed));

This solved the problem