jsx.jsx

getUserById: function (id) {

  	var self = this;

  	return new Promise( function( resolve, reject ){

  		if ( id ){
  			var context = new SP.ClientContext.get_current();
  			var userInfoList = context.get_web().get_siteUserInfoList();
  			var query = new SP.CamlQuery();
  			var viewXml = "<View> \
							<Query> \
							   <Where> \
								   <Eq><FieldRef Name='ID' /><Value Type='Text'>" + id + "</Value></Eq> \
							   </Where>  \
							</Query> \
							<RowLimit>1</RowLimit> \
						  </View>";
  			query.set_viewXml(viewXml);
		   
  			var items = userInfoList.getItems(query);
  			context.load(items,'Include(EMail,ID,Name,SipAddress,UserName)');
		   
  			context.executeQueryAsync(function(){
  				if(items.get_count() > 0) {
  					var item = items.itemAt(0);
  					var data = item.get_fieldValues();
  					resolve( data.Name );
  				}
  			},
			  function ( err ) {
			  	reject("No Matches: " + err);
			  }
			);
  		}

  	});
  }