Remove autoSkip logic to always display last tick (#5891)

This changes the behavior of `autoSkip` so that it does not force the
display of the last tick. If the last tick can be displayed with equal
spacing to the rest of the ticks, it will be. Otherwise, it is not.

diff --git a/src/core/core.scale.js b/src/core/core.scale.js
index 02e36d99051ba9d8191c4dcb3b6f8d133214ccbe..45ba93bd7391a2a447cd5278043e8714ba883087 100644 (file)
--- a/src/core/core.scale.js
+++ b/src/core/core.scale.js
@@ -644,7 +644,7 @@ module.exports = Element.extend({
                var cosRotation = Math.cos(labelRotationRadians);
                var longestRotatedLabel = me.longestLabelWidth * cosRotation;
                var result = [];
-               var i, tick, shouldSkip;
+               var i, tick;
 
                // figure out the maximum number of gridlines to show
                var maxTicks;
@@ -669,9 +669,7 @@ module.exports = Element.extend({
                for (i = 0; i < tickCount; i++) {
                        tick = ticks[i];
 
-                       // Since we always show the last tick,we need may need to hide the last shown one before
-                       shouldSkip = (skipRatio > 1 && i % skipRatio > 0) || (i % skipRatio === 0 && i + skipRatio >= tickCount);
-                       if (shouldSkip && i !== tickCount - 1) {
+                       if (skipRatio > 1 && i % skipRatio > 0) {
                                // leave tick in place but make sure it's not displayed (#4635)
                                delete tick.label;
                        }

diff --git a/test/specs/core.scale.tests.js b/test/specs/core.scale.tests.js
index 20890bb77204d5afe85f9650436b5665b99926c2..35ef3d6babbf84c00db2b91080e61d36f6364a99 100644 (file)
--- a/test/specs/core.scale.tests.js
+++ b/test/specs/core.scale.tests.js
@@ -20,6 +20,60 @@ describe('Core.scale', function() {
                });
        });
 
+       describe('displaying xAxis ticks with autoSkip=true', function() {
+               function getChart(data) {
+                       return window.acquireChart({
+                               type: 'line',
+                               data: data,
+                               options: {
+                                       scales: {
+                                               xAxes: [{
+                                                       ticks: {
+                                                               autoSkip: true
+                                                       }
+                                               }]
+                                       }
+                               }
+                       });
+               }
+
+               function lastTick(chart) {
+                       var xAxis = chart.scales['x-axis-0'];
+                       var ticks = xAxis.getTicks();
+                       return ticks[ticks.length - 1];
+               }
+
+               it('should display the last tick if it fits evenly with other ticks', function() {
+                       var chart = getChart({
+                               labels: [
+                                       'January 2018', 'February 2018', 'March 2018', 'April 2018',
+                                       'May 2018', 'June 2018', 'July 2018', 'August 2018',
+                                       'September 2018'
+                               ],
+                               datasets: [{
+                                       data: [12, 19, 3, 5, 2, 3, 7, 8, 9]
+                               }]
+                       });
+
+                       expect(lastTick(chart).label).toEqual('September 2018');
+               });
+
+               it('should not display the last tick if it does not fit evenly', function() {
+                       var chart = getChart({
+                               labels: [
+                                       'January 2018', 'February 2018', 'March 2018', 'April 2018',
+                                       'May 2018', 'June 2018', 'July 2018', 'August 2018',
+                                       'September 2018', 'October 2018', 'November 2018', 'December 2018'
+                               ],
+                               datasets: [{
+                                       data: [12, 19, 3, 5, 2, 3, 7, 8, 9, 10, 11, 12]
+                               }]
+                       });
+
+                       expect(lastTick(chart).label).toBeUndefined();
+               });
+       });
+
        var gridLineTests = [{
                labels: ['tick1', 'tick2', 'tick3', 'tick4', 'tick5'],
                offsetGridLines: false,