port beginSlice, endSlice dataGrid -> dataTable

basic pagination support
thanks again @calvino

fixes #101

Author: gordonwoodhull

spec/data-table-spec.js

@@ -75,6 +75,24 @@ describe('dc.dataTable', function () {
         });
     });
 
+    describe('slicing entries', function () {
+        beforeEach(function () {
+            chart.beginSlice(1);
+            chart.redraw();
+        });
+
+        it('slice beginning', function () {
+            expect(chart.selectAll('tr.dc-table-row')[0].length).toEqual(2);
+        });
+
+        it('slice beginning and end', function () {
+            chart.endSlice(2);
+            chart.redraw();
+
+            expect(chart.selectAll('tr.dc-table-row')[0].length).toEqual(1);
+        });
+    });
+
     describe('external filter', function () {
         beforeEach(function () {
             countryDimension.filter('CA');

src/data-table.js

@@ -34,6 +34,8 @@ dc.dataTable = function (parent, chartGroup) {
         return d;
     };
     var _order = d3.ascending;
+    var _beginSlice = 0;
+    var _endSlice;
     var _showGroups = true;
 
     _chart._doRender = function () {
@@ -155,7 +157,7 @@ dc.dataTable = function (parent, chartGroup) {
             .sortKeys(_order)
             .entries(entries.sort(function (a, b) {
                 return _order(_sortBy(a), _sortBy(b));
-            }));
+            }).slice(_beginSlice, _endSlice));
     }
 
     function renderRows (groups) {
@@ -202,6 +204,34 @@ dc.dataTable = function (parent, chartGroup) {
         return _chart;
     };
 
+    /**
+     #### .beginSlice([index])
+     Get or set the index of the beginning slice which determines which entries get displayed by the widget
+     Useful when implementing pagination.
+
+     **/
+    _chart.beginSlice = function (_) {
+        if (!arguments.length) {
+            return _beginSlice;
+        }
+        _beginSlice = _;
+        return _chart;
+    };
+
+    /**
+     #### .endSlice([index])
+     Get or set the index of the end slice which determines which entries get displayed by the widget
+     Useful when implementing pagination.
+
+     **/
+    _chart.endSlice = function (_) {
+        if (!arguments.length) {
+            return _endSlice;
+        }
+        _endSlice = _;
+        return _chart;
+    };
+
     /**
      * Get or set column functions. The data table widget now supports several methods of specifying
      * the columns to display.  The original method, first shown below, uses an array of functions to