Allow tooltipFormat to be a function. Provide a default tooltipFormat

docs/axes/cartesian/time.md

@@ -36,7 +36,7 @@ The following options are provided by the time scale. You may also set options p
 | `time.min` | [Time](#date-formats) | | If defined, this will override the data minimum
 | `time.parser` | `String` or `Function` | | Custom parser for dates. [more...](#parser)
 | `time.round` | `String` | `false` | If defined, dates will be rounded to the start of this unit. See [Time Units](#time-units) below for the allowed units.
-| `time.tooltipFormat` | `String` | | The moment js format string to use for the tooltip.
+| `time.tooltipFormat` | `String|Function` | | The moment js format string to use for the tooltip. [more...](#tooltip-format)
 | `time.unit` | `String` | `false` | If defined, will force the unit to be a certain type. See [Time Units](#time-units) section below for details.
 | `time.stepSize` | `Number` | `1` | The number of units between grid lines.
 | `time.minUnit` | `String` | `'millisecond'` | The minimum display format to be used for a time unit.
@@ -147,6 +147,11 @@ The `ticks.source` property controls the ticks generation
 * `'labels'`: generates ticks from user given `data.labels` values ONLY
 
 ### Parser
-If this property is defined as a string, it is interpreted as a custom format to be used by moment to parse the date. 
+If this property is defined as a string, it is interpreted as a custom format to be used by Moment.js to parse the date. 
 
-If this is a function, it must return a moment.js object given the appropriate data value.
+If this is a function, it must return a Moment.js object given the appropriate data value.
+
+### Tooltip Format
+If this property is defined as a string, it is interpreted as a custom format to be used by Moment.js to format the date. 
+
+If this is a function, it must return a custom format to be used by Moment.js to format the date.

src/scales/scale.time.js

@@ -231,6 +231,11 @@ function parse(input, scale) {
 /**
  * Returns the number of unit to skip to be able to display up to `capacity` number of ticks
  * in `unit` for the given `min` / `max` range and respecting the interval steps constraints.
+ * @param min {number} minimum tick millis
+ * @param max {number} maximum tick millis
+ * @param unit {string} the time unit the ticks are being displayed as
+ * @param capacity {number} the number of labels we have room to display
+ * @return {string} the number of ticks to skip before displaying the next one
  */
 function determineStepSize(min, max, unit, capacity) {
  var range = max - min;
@@ -380,6 +385,21 @@ function ticksFromTimestamps(values, majorUnit) {
  return ticks;
 }
 
+/**
+ * Show the most specific time format by default
+ */
+function defaultTooltipFormat(context) {
+ var value = context.dataset.data[context.dataIndex];
+ var momentDate = momentify(value, context.options.time);
+ if (momentDate.millisecond() !== 0) {
+ return 'MMM D, YYYY h:mm:ss.SSS a';
+ }
+ if (momentDate.second() !== 0 || momentDate.minute() !== 0 || momentDate.hour() !== 0) {
+ return 'MMM D, YYYY h:mm:ss a';
+ }
+ return 'MMM D, YYYY';
+}
+
 module.exports = function(Chart) {
 
  var defaultConfig = {
@@ -411,6 +431,7 @@ module.exports = function(Chart) {
  displayFormat: false, // DEPRECATED
  isoWeekday: false, // override week start day - see http://momentjs.com/docs/#/get-set/iso-weekday/
  minUnit: 'millisecond',
+ tooltipFormat: defaultTooltipFormat,
 
  // defaults to unit's corresponding unitFormat below or override using pattern string from http://momentjs.com/docs/#/displaying/format/
  displayFormats: {
@@ -606,19 +627,31 @@ module.exports = function(Chart) {
 
  getLabelForIndex: function(index, datasetIndex) {
  var me = this;
- var data = me.chart.data;
- var timeOpts = me.options.time;
+ var chart = me.chart;
+ var data = chart.data;
+ var options = me.options;
+ var timeOpts = options.time;
+ var tooltipFormat = timeOpts.tooltipFormat;
  var label = data.labels && index < data.labels.length ? data.labels[index] : '';
  var value = data.datasets[datasetIndex].data[index];
+ var context = {
+ chart: chart,
+ options: options,
+ dataIndex: index,
+ dataset: chart.data.datasets[datasetIndex],
+ datasetIndex: datasetIndex
+ };
+ var momentDate;
 
- if (helpers.isObject(value)) {
- label = me.getRightValue(value);
- }
- if (timeOpts.tooltipFormat) {
- label = momentify(label, timeOpts).format(timeOpts.tooltipFormat);
+ if (!helpers.isObject(value)) {
+ return label;
  }
 
- return label;
+ momentDate = momentify(me.getRightValue(value), timeOpts);
+ tooltipFormat = typeof tooltipFormat === 'function'
+ ? tooltipFormat.call(me, context)
+ : tooltipFormat;
+ return momentDate.format(tooltipFormat);
  },
 
  /**

test/specs/scale.time.tests.js

@@ -102,6 +102,7 @@ describe('Time scale tests', function() {
  isoWeekday: false,
  displayFormat: false,
  minUnit: 'millisecond',
+ tooltipFormat: defaultConfig.time.tooltipFormat,
  displayFormats: {
  millisecond: 'h:mm:ss.SSS a', // 11:20:01.123 AM
  second: 'h:mm:ss a', // 11:20:01 AM