Chart.js/docs/axes/cartesian/time.md

Time Cartesian Axis

The time scale is used to display times and dates. When building its ticks, it will automatically calculate the most comfortable unit base on the size of the scale.

Configuration Options

The following options are provided by the time scale. They are all located in the time sub options. These options extend the common tick configuration.

Name	Type	Default	Description
displayFormats	Object		Sets how different time units are displayed. more...
isoWeekday	Boolean	false	If true and the unit is set to 'week', iso weekdays will be used.
max	Time		If defined, this will override the data maximum
min	Time		If defined, this will override the data minimum
parser	String or Function		Custom parser for dates. more...
round	String	false	If defined, dates will be rounded to the start of this unit. See Time Units below for the allowed units.
tooltipFormat	String		The moment js format string to use for the tooltip.
unit	String	false	If defined, will force the unit to be a certain type. See Time Units section below for details.
unitStepSize	Number	1	The number of units between grid lines.
minUnit	String	millisecond	The minimum display format to be used for a time unit.

Date Formats

When providing data for the time scale, Chart.js supports all of the formats that Moment.js accepts. See Moment.js docs for details.

Time Units

The following time measurements are supported. The names can be passed as strings to the time.unit config option to force a certain unit.

• millisecond
• second
• minute
• hour
• day
• week
• month
• quarter
• year

For example, to create a chart with a time scale that always displayed units per month, the following config could be used.

var chart = new Chart(ctx, {
    type: 'line',
    data: data,
    options: {
        scales: {
            xAxes: [{
                time: {
                    unit: 'month'
                }
            }]
        }
    }
})

Display Formats

The following display formats are used to configure how different time units are formed into strings for the axis tick marks. See moment.js for the allowable format strings.

Name	Default
millisecond	'SSS [ms]'
second	'h:mm:ss a'
minute	'h:mm:ss a'
hour	'MMM D, hA'
day	'll'
week	'll'
month	'MMM YYYY'
quarter	'[Q]Q - YYYY'
year	'YYYY'

For example, to set the display format for the 'quarter' unit to show the month and year, the following config would be passed to the chart constructor.

var chart = new Chart(ctx, {
    type: 'line',
    data: data,
    options: {
        scales: {
            xAxes: [{
                type: 'time',
                time: {
                    displayFormats: {
                        quarter: 'MMM YYYY'
                    }
                }
            }]
        }
    }
})

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 is a function, it must return a moment.js object given the appropriate data value.