fixed tooltip labelling on Bar Chart when min is defined

added helper method to adjust the index

pass in chartConfig rather than access within method, make it easier to
test

added semi-colon at the end of helper method

added test for adjustIndex helper method

fixed lint issues

added integration test for the interaction of trigger an event over the
bar

.

.

moved adjustIndex into element helper

removed method from helper and adjusted method in core.interaction

added test for the element adjustIndex helper

added a skipIndexAdjustment method to handle when to skip the adjustment
along with test cases

fixed lint issues

removed the test for the helper method

src/core/core.element.js

@@ -88,6 +88,24 @@ module.exports = function(Chart) {
 
 		hasValue: function() {
 			return helpers.isNumber(this._model.x) && helpers.isNumber(this._model.y);
+		},
+
+
+		skipIndexAdjustment: function(config) {
+			var moreThanOneAxes = config.options.scales.xAxes.length > 1;
+			var min = config.options.scales.xAxes[0].ticks.min;
+			return this._adjustedIndex || min === undefined || moreThanOneAxes;
+		},
+
+		adjustIndex: function(config) {
+			var min = config.options.scales.xAxes[0].ticks.min;
+
+			if (this.skipIndexAdjustment(config)) {
+				return;
+			}
+
+			this._index -= config.data.labels.indexOf(min);
+			this._adjustedIndex = true;
 		}
 	});
 

src/core/core.interaction.js

@@ -21,6 +21,7 @@ module.exports = function(Chart) {
 			for (j = 0, jlen = meta.data.length; j < jlen; ++j) {
 				var element = meta.data[j];
 				if (!element._view.skip) {
+					element.adjustIndex(chart.config);
 					handler(element);
 				}
 			}

test/core.element.tests.js

@@ -42,4 +42,88 @@ describe('Core element tests', function() {
 			colorProp: 'rgb(64, 64, 0)',
 		});
 	});
+
+	it ('should adjust the index of the element passed in', function() {
+		var chartConfig = {
+			options: {
+				scales: {
+					xAxes: [{
+						ticks: {
+							min: 'Point 2'
+						}
+					}]
+				}
+			},
+			data: {
+				labels: ['Point 1', 'Point 2', 'Point 3']
+			}
+		};
+
+		var element = new Chart.Element({
+			_index: 1
+		});
+
+		element.adjustIndex(chartConfig);
+
+		expect(element._adjustedIndex).toEqual(true);
+		expect(element._index).toEqual(0);
+	});
+
+	describe ('skipIndexAdjustment method', function() {
+		var element;
+
+		beforeEach(function() {
+			element = new Chart.Element({});
+		});
+
+		it ('should return true when min is undefined', function() {
+			var chartConfig = {
+				options: {
+					scales: {
+						xAxes: [{
+							ticks: {
+								min: undefined
+							}
+						}]
+					}
+				}
+			};
+			expect(element.skipIndexAdjustment(chartConfig)).toEqual(true);
+		});
+
+		it ('should return true when index is already adjusted (_adjustedIndex = true)', function() {
+			var chartConfig = {
+				options: {
+					scales: {
+						xAxes: [{
+							ticks: {
+								min: 'Point 1'
+							}
+						}]
+					}
+				}
+			};
+			element._adjustedIndex = true;
+			expect(element.skipIndexAdjustment(chartConfig)).toEqual(true);
+		});
+
+		it ('should return true when more than one xAxes is defined', function() {
+			var chartConfig = {
+				options: {
+					scales: {
+						xAxes: [{
+							ticks: {
+								min: 'Point 1'
+							}
+						}, {
+							ticks: {
+								min: 'Point 2'
+							}
+						}]
+					}
+				}
+			};
+			expect(element.skipIndexAdjustment(chartConfig)).toEqual(true);
+		});
+	});
 });

test/core.interaction.tests.js

@@ -43,6 +43,57 @@ describe('Core.Interaction', function() {
 			expect(elements).toEqual([point, meta1.data[1]]);
 		});
 
+		it ('should start at index 0 within sliced dataset when min is defined', function() {
+			var chartInstance = window.acquireChart({
+				type: 'line',
+				options: {
+					scales: {
+						xAxes: [{
+							ticks: {
+								min: 'March',
+								max: 'May'
+							},
+							categoryPercentage: 1,
+							barPercentage: 1,
+						}]
+					}
+				},
+				data: {
+					datasets: [{
+						label: 'Dataset 1',
+						data: [10, 30, 39, 20, 25, 34, 1],
+					}, {
+						label: 'Dataset 2',
+						data: [10, 30, 39, 20, 25, 34, 1],
+					}],
+					labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July'],
+				}
+			});
+
+			// Trigger an event over top of the
+			var meta0 = chartInstance.getDatasetMeta(0);
+			var point = meta0.data[2];
+
+			var node = chartInstance.chart.canvas;
+			var rect = node.getBoundingClientRect();
+
+			var evt = {
+				view: window,
+				bubbles: true,
+				cancelable: true,
+				clientX: rect.left + point._model.x,
+				clientY: rect.top + point._model.y,
+				currentTarget: node
+			};
+
+			var elements = Chart.Interaction.modes.point(chartInstance, evt);
+
+			elements.forEach(function(element) {
+				expect(element._index).toEqual(0);
+				expect(element._adjustedIndex).toBeTruthy();
+			});
+		});
+
 		it ('should return an empty array when no items are found', function() {
 			var chartInstance = window.acquireChart({
 				type: 'line',