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Numbers and dates

Korean units, K/M, "in millions", currency, decimals, date patterns and time zones.

Axis ticks are short; tooltips and tables are exact. On English pages the axis reads 12.3K · 340M and the tooltip 123,456,789; on Korean pages the axis uses 만·억.

numberFormat

Value	12,345 →	340,000,000 →	Used for
`'korean'`	1.2만	3.4억	Default on Korean pages
`'compact'`	12.3K	340M	Default in other languages
`'comma'`	12,345	340,000,000	Reports that need exact numbers
`'percent'`	12,345%	-	Values that already are percents (pass 50, not 0.5)
a function	`(v) => string`		Used for the axis and the tooltip

To change only the axis ticks, give the same value to yAxis: { format } (or xAxis). The helpers are exported too.

import { korean, compact, comma } from '@82chart/core';
korean(123456789);  // '1.2억'
compact(123456789); // '123.5M'
comma(1234.5);      // '1,234.5'

"In millions" reports

For report-style axes in millions with commas, divide with scale and add a unit. With a scale, the axis, tooltip and table all show the divided number with the unit, while the headline value stays the full amount. State the unit in a footnote.

Live example

Code for this example

createChart('#chart', {
  type: 'bar',
  title: 'Revenue by division',
  scale: 1000000,
  unit: 'M',
  footnote: 'In millions of won',
  data: {
    labels: ['Domestic', 'Overseas', 'Online', 'Wholesale'],
    series: [{ name: 'Revenue', data: [1820000000, 940000000, 2310000000, 610000000] }],
  },
});

Option	What it does
`unit`	After the value: `'%'`, `' users'`, `'M'`
`prefix`	Before the value: `'$'`, `'₩ '`. With `scale`, the tooltip shows the full amount ($1,820,000,000)
`scale`	Divide axis ticks by this (1000000 → millions)
`decimals`	Decimals in tooltips and labels (default: up to 2, trailing zeros trimmed)

Dates

Time axis labels follow the spacing: months as Jan · Feb (with the year when it changes), days as Oct 21, hours as 09:00. Tooltips show the full date. Pass a pattern to dateFormat to choose yourself.

Token	Meaning	Example
`YYYY` / `YY`	Year	2026 / 26
`M` / `MM`	Month	3 / 03
`MMM`	Month name (languages that have them)	Mar
`D` / `DD`	Day	7 / 07
`ddd`	Weekday	Tue
`H` / `HH`	Hour	9 / 09
`mm` / `ss`	Minutes / seconds	05 / 30

createChart('#chart', {
  type: 'line',
  dateFormat: 'MMM D (ddd)', // Oct 21 (Tue)
  data: { series: [{ name: 'Visitors', data: [['2026-10-20', 1820], ['2026-10-21', 2140]] }] },
});

dateFormat is used for both the axis and the tooltip; 'auto' is the default behaviour.

Time zone (timeZone)

Dates are read and written in the runtime's zone by default. That is fine in browsers, but servers (Cloudflare Workers, most Node hosts) run on UTC, so renderToSVG there puts Korean midnight data on the previous day. Give timeZone an IANA name and the axis, tooltip, table and CSV all use that zone. Date-only strings such as '2026-10-21' are that day in the zone, and '2026-10-21T09:00' without an offset is 9 o'clock there.

createChart('#chart', {
  type: 'line',
  timeZone: 'America/New_York', // the same labels wherever it runs
  data: { series: [{ name: 'Orders', data: [['2026-10-21T04:00:00Z', 120], ['2026-10-21T10:00:00Z', 180]] }] },
});

An unknown zone name logs one warning and falls back to the runtime zone. The exported helper formatDate(date, pattern, locale, timeZone) takes the zone as its fourth argument.