Update header dynamically

Author: RoXuS

paper-datatable-column.html

@@ -39,7 +39,11 @@
 					 * @type String
 					 * @required
 					 */
-					header: String,
+					header: {
+						type: String,
+						notify: true,
+						observer: '_headerChanged'
+					},
 					/**
 					 * The property to be used from `data` for this column
 					 *
@@ -434,8 +438,10 @@
 					}else if(type.toLowerCase() == 'number'){
 						return 'number';
 					}
-				}
-
+				},
+				_headerChanged: function(header) {
+					this.fire('header-changed');
+				},
 
 			});
 		})();

paper-datatable.html

@@ -510,13 +510,15 @@
 
 				_queryAndSetColumns: function(){
 					var columns = this.queryAllEffectiveChildren('paper-datatable-column');
-					columns.forEach((column) => {
+					columns.forEach((column, index) => {
 						if(!column.beenAttached.state.ready){
 							column.parentNodeRef = this;
 							this.async(function(){
 								column._registerEvilFunctions();
 								column.beenAttached.ready();
 							});
+							column.index = index;
+							this.listen(column, 'header-changed', '_updateHeaderColumn');
 						}
 					});
 					this.set('_columns', columns.filter((column) => !column.inactive));
@@ -1098,7 +1100,11 @@
 
 						}
 					}
-				}
+				},
+				_updateHeaderColumn: function(event){
+					var column = Polymer.dom(event).localTarget;
+					this.notifyPath(`_columns.${column.index}.header`, this._columns[column.index].header);
+				},
 
 			});
 		})();