Hide chart when setData is passed empty or null array. (Fixes #142)

lib/morris.bar.coffee

@@ -116,6 +116,7 @@ class Morris.Bar extends Morris.Grid
   # hit test - returns the index of the row beneath the given coordinate
   #
   hitTest: (x, y) ->
+    return null if @data.length == 0
     x = Math.max(Math.min(x, @right), @left)
     Math.min(@data.length - 1,
       Math.floor((x - @left) / (@width / @data.length)))

lib/morris.grid.coffee

@@ -94,6 +94,12 @@ class Morris.Grid extends Morris.EventEmitter
   # Update the data series and redraw the chart.
   #
   setData: (data, redraw = true) ->
+    if !data? or data.length == 0
+      @data = []
+      @raphael.clear()
+      @hover.hide() if @hover?
+      return
+
     ymax = if @cumulative then 0 else null
     ymin = if @cumulative then 0 else null
 

lib/morris.line.coffee

@@ -59,6 +59,7 @@ class Morris.Line extends Morris.Grid
   # hit test - returns the index of the row beneath the given coordinate
   #
   hitTest: (x, y) ->
+    return null if @data.length == 0
     # TODO better search algo
     for r, index in @data.slice(1)
       break if x < (r._x + @data[index]._x) / 2

morris.js

@@ -145,6 +145,14 @@
       if (redraw == null) {
         redraw = true;
       }
+      if (!(data != null) || data.length === 0) {
+        this.data = [];
+        this.raphael.clear();
+        if (this.hover != null) {
+          this.hover.hide();
+        }
+        return;
+      }
       ymax = this.cumulative ? 0 : null;
       ymin = this.cumulative ? 0 : null;
       if (this.options.goals.length > 0) {
@@ -636,6 +644,9 @@
 
     Line.prototype.hitTest = function(x, y) {
       var index, r, _i, _len, _ref;
+      if (this.data.length === 0) {
+        return null;
+      }
       _ref = this.data.slice(1);
       for (index = _i = 0, _len = _ref.length; _i < _len; index = ++_i) {
         r = _ref[index];
@@ -1291,6 +1302,9 @@
     };
 
     Bar.prototype.hitTest = function(x, y) {
+      if (this.data.length === 0) {
+        return null;
+      }
       x = Math.max(Math.min(x, this.right), this.left);
       return Math.min(this.data.length - 1, Math.floor((x - this.left) / (this.width / this.data.length)));
     };

spec/lib/grid/set_data_spec.coffee

@@ -174,4 +174,15 @@ describe 'Morris.Grid#setData', ->
     line.ymax.should == 16
     line.data.map((row) -> row.y).should.deep.equal [[13.5], [12], [16], [14]]
 
-
+  it 'should clear the chart when empty data is supplied', ->
+    line = Morris.Line
+      element: 'graph',
+      data: [{x: 2, y: '12'}, {x: 1, y: '13.5'}, {x: 4, y: '14'}, {x: 3, y: '16'}]
+      xkey: 'x'
+      ykeys: ['y']
+      labels: ['y']
+    line.data.length.should.equal 4
+    line.setData([])
+    line.data.length.should.equal 0
+    line.setData([{x: 2, y: '12'}, {x: 1, y: '13.5'}, {x: 4, y: '14'}, {x: 3, y: '16'}])
+    line.data.length.should.equal 4