[Timeline fix #2814] Do not corrupt class names at high zoom levels. (#2909)

This takes a more robust approach to produce the list of class names.

lib/timeline/TimeStep.js

@@ -560,6 +560,7 @@ TimeStep.prototype.getClassName = function() {
   var m = this.moment(this.current);
   var current = m.locale ? m.locale('en') : m.lang('en'); // old versions of moment have .lang() function
   var step = this.step;
+  var classNames = [];
 
   function even(value) {
     return (value / step % 2 == 0) ? ' vis-even' : ' vis-odd';
@@ -592,51 +593,49 @@ TimeStep.prototype.getClassName = function() {
 
   switch (this.scale) {
     case 'millisecond':
-      return today(current) +
-        even(current.milliseconds()).trim();
-
+      classNames.push(today(current));
+      classNames.push(even(current.milliseconds()));
+      break;
     case 'second':
-      return today(current) +
-        even(current.seconds()).trim();
-
+      classNames.push(today(current));
+      classNames.push(even(current.seconds()));
+      break;
     case 'minute':
-      return today(current) +
-        even(current.minutes()).trim();
-
+      classNames.push(today(current));
+      classNames.push(even(current.minutes()));
+      break;
     case 'hour':
-      return 'vis-h' + current.hours() + 
-        (this.step == 4 ? '-h' + (current.hours() + 4) : '') +
-        today(current) +
-        even(current.hours());
-
+      classNames.push('vis-h' + current.hours() + this.step == 4 ? '-h' + (current.hours() + 4) : '');
+      classNames.push(today(current));
+      classNames.push(even(current.hours()));
+      break;
     case 'weekday':
-      return 'vis-' + current.format('dddd').toLowerCase() +
-        today(current) +
-        currentWeek(current) +
-        even(current.date());
-
+      classNames.push('vis-' + current.format('dddd').toLowerCase());
+      classNames.push(today(current));
+      classNames.push(currentWeek(current));
+      classNames.push(even(current.date()));
+      break;
     case 'day':
-      return 'vis-day' + current.date() +
-        ' vis-' + current.format('MMMM').toLowerCase() +
-        today(current) +
-        currentMonth(current) +
-        (this.step <= 2 ? today(current) : '') +
-        (this.step <= 2 ? ' vis-' + current.format('dddd').toLowerCase() : '' + even(current.date() - 1));
-
+      classNames.push('vis-day' + current.date());
+      classNames.push('vis-' + current.format('MMMM').toLowerCase());
+      classNames.push(today(current));
+      classNames.push(currentMonth(current));
+      classNames.push(this.step <= 2 ? today(current) : '');
+      classNames.push(this.step <= 2 ? 'vis-' + current.format('dddd').toLowerCase() : '');
+      classNames.push(even(current.date() - 1));
+      break;
     case 'month':
-      return 'vis-' + current.format('MMMM').toLowerCase() +
-        currentMonth(current) +
-        even(current.month());
-
+      classNames.push('vis-' + current.format('MMMM').toLowerCase());
+      classNames.push(currentMonth(current));
+      classNames.push(even(current.month()));
+      break;
     case 'year':
-      var year = current.year();
-      return 'vis-year' + year +
-        currentYear(current) +
-        even(year);
-
-    default:
-      return '';
+      classNames.push('vis-year' + current.year());
+      classNames.push(currentYear(current));
+      classNames.push(even(current.year()));
+      break;
   }
+  return classNames.filter(String).join(" ");
 };
 
 module.exports = TimeStep;

test/TimeStep.test.js

@@ -0,0 +1,44 @@
+var assert = require('assert');
+var vis = require('../dist/vis');
+var jsdom = require('mocha-jsdom')
+var moment = vis.moment;
+var timeline = vis.timeline;
+var TimeStep = timeline.TimeStep;
+var TestSupport = require('./TestSupport');
+
+describe('TimeStep', function () {
+  
+  jsdom();
+
+  it('should work with just start and end dates', function () {
+    var timestep = new TimeStep(new Date(2017, 3, 3), new Date(2017, 3, 5));
+    assert.equal(timestep.autoScale, true, "should autoscale if scale not specified");
+    assert.equal(timestep.scale, "day", "should default to day scale if scale not specified");
+    assert.equal(timestep.step, 1, "should default to 1 day step if scale not specified");
+  });
+
+  it('should work with specified scale (just under 1 second)', function () {
+    var timestep = new TimeStep(new Date(2017, 3, 3), new Date(2017, 3, 5), 999);
+    assert.equal(timestep.scale, "second", "should have right scale");
+    assert.equal(timestep.step, 1, "should have right step size");
+  });
+
+  // TODO: check this - maybe should work for 1000?
+  it('should work with specified scale (1 second)', function () {
+    var timestep = new TimeStep(new Date(2017, 3, 3), new Date(2017, 3, 5), 1001);
+    assert.equal(timestep.scale, "second", "should have right scale");
+    assert.equal(timestep.step, 5, "should have right step size");
+  });
+
+  it('should work with specified scale (2 seconds)', function () {
+    var timestep = new TimeStep(new Date(2017, 3, 3), new Date(2017, 3, 5), 2000);
+    assert.equal(timestep.scale, "second", "should have right scale");
+    assert.equal(timestep.step, 5, "should have right step size");
+  });
+
+  it('should work with specified scale (5 seconds)', function () {
+    var timestep = new TimeStep(new Date(2017, 3, 3), new Date(2017, 3, 5), 5001);
+    assert.equal(timestep.scale, "second", "should have right scale");
+    assert.equal(timestep.step, 10, "should have right step size");
+  });
+});