Number ticker
Shows a number that changes — a count, a price, a score, a figure on a dashboard — by moving each changed digit to its new value, so that a person sees that it changed, which way and roughly by how much, while assistive technology is told only the value it settles on.
- Category
- Communication
- Tokens
comp.number-ticker- Level
- Base
- Web
tanrei-number-tickerclock_loader_40 - SwiftUI
TanreiNumberTickerradio_button_unchecked - Jetpack Compose
TanreiNumberTickerradio_button_unchecked - Flutter
TanreiNumberTickerradio_button_unchecked - React Native
NumberTickerradio_button_unchecked
Generated from docs/status/status.json, specs/number-ticker.spec.json
Figures that rise to their values when they come into view
The Web and React samples show the current spec. SwiftUI, Compose, Flutter and React Native are planned: they do not ship a number ticker yet.
<tanrei-number-ticker value="1234" label="Orders"></tanrei-number-ticker>
<tanrei-number-ticker value="98400" number-style="currency" currency="USD" label="Revenue"></tanrei-number-ticker>
<!-- A dashboard's figure rises from 0 the first time it comes into view. -->
<tanrei-number-ticker start-value="0" value="0.426" number-style="percent" fraction-digits="1"></tanrei-number-ticker>
<!-- A count the person changes: told once each change settles. -->
<tanrei-number-ticker value="2" live="polite" label="Items in cart"></tanrei-number-ticker>
<script type="module">
import '@tanrei/web/components/number-ticker';
const ticker = document.querySelector('tanrei-number-ticker');
ticker.value = orders.length;
ticker.addEventListener('settle', (event) => console.log('now showing', event.detail.value));
</script>import { NumberTicker } from '@tanrei/react';
<NumberTicker value={orders.length} label="Orders" />
<NumberTicker value={revenue} numberStyle="currency" currency="USD" label="Revenue" />
<NumberTicker startValue={0} value={0.426} numberStyle="percent" fractionDigits={1} />
<NumberTicker value={count} live="polite" label="Items in cart" onSettle={(event) => setShown(event.detail.value)} />Animations: slide (the default system's), blur, blur-slide and flip
Trend: auto (19 to 20 moves both digits up) and digit (the ones go down from 9 to 0)
Anatomy
| Part | Description |
|---|---|
1 number | The formatted number, laid out as text in the style of where it stands: every digit in a column of its own, every other character (a sign, a separator, a currency, a unit, a compact suffix) as plain text between them. |
2 digit | One digit's place: a window one digit high showing one digit of a column of the digits 0 to 9 stacked from top to bottom, which moves through the window to show another. |
3 text | The label and the formatted value as one text for assistive technology, not drawn. |
Properties
| Property | Type | Default | Description |
|---|---|---|---|
value | number | 0 | The number shown. |
style | decimal | percent | currency | unit | "decimal" | How the number is written, by the platform's number formatter. percent multiplies by 100 and adds the locale's percent sign; currency writes it as an amount of currency; unit with the unit unit names. |
currency | string | "" | The currency while style is currency, as its three-letter code ("JPY", "EUR"). Not words: the formatter writes the locale's symbol. |
unit | string | "" | The unit while style is unit, as the formatter's identifier of a unit ("kilometer-per-hour", "megabyte"). Not words: the formatter writes the locale's form. |
notation | standard | compact | "standard" | standard writes every digit; compact writes the number short with the locale's suffix (1.2K, 1.2万). |
fractionDigits | number | null | How many digits after the decimal separator are always written. Null leaves it to the formatter for the style (none for a whole decimal, the currency's own for currency). |
signDisplay | auto | always | except-zero | "auto" | When a sign is written: auto for a negative number only; always for every number; except-zero for every number but zero (a change: +12, −3, 0). |
locale | string | "" | The language the number is written in, as a language tag ("ja-JP", "ar-EG"). Empty takes the language of where the ticker stands, and the platform's where none is set. |
trend | auto | up | down | digit | "auto" | Which way the digits move. auto: every changed digit moves the way the whole number moved — up when it grew, down when it shrank — so that 19 to 20 moves both digits up. up and down force one way. digit: each digit moves the way its own value moved, so that 19 to 20 moves the ones down from 9 to 0. |
animation | auto | slide | blur | blur-slide | flip | none | "auto" | How a digit changes. slide: its column moves through the window. blur: the old digit blurs out as the new one sharpens in. blur-slide: both, the new one coming from the side the digit moves from. flip: the upper half of the old digit turns down over the lower half, as a split-flap board. none: at once. auto takes comp.number-ticker.animation, the design system's answer (slide in the default system). |
startValue | number | null | A value to move from the first time the ticker comes into view (a dashboard's figures rising to their values). Null draws the first value at once. |
duration | number | null | How long a change takes, in milliseconds. Null takes comp.number-ticker.motion.duration. |
live | off | polite | "off" | Whether assistive technology is told each new value as it settles. off for a number that is not the point of the moment (most figures); polite for one a person waits for (a counter they are changing, a result arriving). |
label | string | "" | Words read before the value ("Revenue"), where nothing visible beside the number already says what it is. Never drawn. |
Events
| Event | Description |
|---|---|
settle | The digits came to rest at value: once at the end of each change's motion (at once where there is none). Carries value. |
States
Behavior
Requirements in EARS form. Every platform implementation is tested against these ids.
| ID | Requirement |
|---|---|
NTK-1 | THE number ticker SHALL write value with the platform's number formatter in locale (the language of where it stands while locale is empty), with style, currency, unit, notation, fractionDigits and signDisplay, SHALL draw every digit of the result — in the locale's own digits — in a digit place of its own, in tabular figures of the font of where it stands so that every digit is as wide as every other, and every other character the formatter writes as plain text in that font; it SHALL lay the number out inline, in the text style, color and direction of where it stands, as one run isolated from the text around it, and SHALL draw no fill, edge or color of its own. |
NTK-2 | THE number ticker SHALL draw each digit place as a window one line high that shows one digit of a column of the locale's digits 0 to 9 stacked from top to bottom, clipped to the window, so that a greater digit lies lower in the column; to show a digit the column SHALL stand with that digit in the window. |
NTK-3 | WHEN value changes while animation is slide THE number ticker SHALL move the column of every digit place whose digit changes from the old digit to the new one: WHILE trend is digit, down the column toward a greater digit (the column moving up through the window, the new digit rising from below) and up it toward a lesser one; WHILE trend is auto, every changed digit in the direction the whole number moved — toward the greater digits when value grew and toward the lesser when it shrank — going on past 9 to 0 (or back past 0 to 9) where the new digit lies the other way, so that 19 to 20 moves the ones one step on from 9 to 0 and the tens one step on from 1 to 2; WHILE trend is up or down, every changed digit in that direction as auto does for a number that grew or shrank. Each column SHALL move over the change's duration (duration, or comp.number-ticker.motion.duration while it is null) with comp.number-ticker.motion.easing, each digit place, from the most significant to the least, starting comp.number-ticker.motion.stagger after the one before it. |
NTK-4 | WHEN value changes while animation is blur THE number ticker SHALL cross-fade each changed digit over the change's duration, the old digit blurring from none to comp.number-ticker.blur.radius as it fades out and the new one sharpening from that radius to none as it fades in; WHILE animation is blur-slide it SHALL do the same while moving the old digit out and the new one in by comp.number-ticker.blur-slide.distance in the direction slide would (NTK-3); WHILE animation is flip it SHALL turn the upper half of the old digit down about the digit's middle over the lower half, showing the upper half of the new digit behind it and then its lower half, as a split-flap board, over the change's duration with comp.number-ticker.motion.easing. |
NTK-5 | WHEN the formatted number gains or loses characters (99 to 100, 999 to 1,000, a sign that appears) THE number ticker SHALL move its width to the new one with the digits' motion, keeping its end edge still WHILE it is aligned to the end of where it stands and its start edge still otherwise; a digit place that appears SHALL slide in with its column from the side the change moves from and fade in, one that goes SHALL slide out the other way and fade out, and a character that is not a digit SHALL fade in or out in its place. |
NTK-6 | WHEN value changes again before a change's motion has ended THE number ticker SHALL move every digit place from where it is drawn at that moment to the new digit, by the rule of NTK-3 for the new change, and SHALL never jump to a digit first; the change's duration SHALL start again from that moment. |
NTK-7 | WHERE motion is reduced, or WHILE animation is none, THE number ticker SHALL show the new number at once, its width included — cross-fading the old number to the new one over comp.number-ticker.motion.reduced-duration where motion is reduced and the platform can fade — and SHALL emit settle at once. |
NTK-8 | WHEN the ticker first comes into view WHILE startValue is not null THE number ticker SHALL draw startValue and move to value as a change of NTK-3 and NTK-4, once; WHILE startValue is null, and on every later first drawing, it SHALL draw value at once without a motion. |
NTK-9 | THE number ticker SHALL expose to assistive technology one text — label where it is not empty, then the number written as NTK-1 says — and SHALL hide every drawn digit, column and character from it, so that the number is read once, as written, and never digit by digit or as the digits passing through the windows; the text SHALL be the current value, in place, read where the ticker stands — WHILE live is polite, the value of the last change that settled (NTK-10). |
NTK-10 | WHILE live is polite THE number ticker SHALL tell assistive technology the text of NTK-9, politely and without moving focus, once WHEN a change's motion ends — the text itself changing only then, so that what a region holds is what it says — and SHALL tell it no value in between, nor any value of a change that a later change replaced before it ended; WHILE live is off it SHALL tell it nothing by itself. |
NTK-11 | WHEN the digits come to rest at value THE number ticker SHALL emit settle once with value; a change that a later change replaces before its end SHALL emit none. |
NTK-12 | IF value is not a finite number THE number ticker SHALL draw what the formatter writes for it (the locale's sign for infinity, or its word for a value that is not a number) as plain text at once, without a motion, and in debug builds report it; IF style is currency and currency is not a code the formatter knows, or style is unit and unit is not a unit it knows, THE number ticker SHALL write the number as decimal and in debug builds report the value. |
NTK-13 | WHERE the layout direction is right-to-left THE number ticker SHALL lay out the number as the formatter writes it for its locale — digits in the order the locale writes them, which is left to right in every locale, isolated from the text around it — and SHALL move its columns up and down as in a left-to-right layout; only the side it stands at and the edge NTK-5 keeps still follow the direction. |
NTK-14 | THE number ticker SHALL take its layout direction and its language from where it is used — the nearest ancestor that sets one, and the platform's own where none does — and SHALL have no direction setting of its own; WHEN either changes while the ticker is shown THE number ticker SHALL write and draw the number for the new one at once, without a motion. |
NTK-15 | WHILE the text size is enlarged THE number ticker SHALL grow with the text it stands in, its windows a line of the larger text high and its motion's distances with them. |
NTK-16 | WHEN animation names a value the active design system does not have, or trend, style, notation, signDisplay or live a value the component does not define, THE number ticker SHALL use the default value (auto, decimal, standard, auto, off) and in debug builds report the unknown value; WHEN duration is not a positive number, or fractionDigits not a whole number from 0 to 100, THE number ticker SHALL treat it as null and in debug builds report it. |
NTK-17 | THE number ticker SHALL have no words of its own and SHALL read none of the product's words: label is about this one number, and every sign, separator, symbol and suffix is the platform's formatter's, in the locale. |
Platform name mapping
Parity does not mean identical APIs. Each platform uses its own idiom for the same contract.
| Spec | Web | SwiftUI | Jetpack Compose | Flutter | React Native |
|---|---|---|---|---|---|
| Component | tanrei-number-ticker | TanreiNumberTicker | TanreiNumberTicker | TanreiNumberTicker | NumberTicker |
value · Property | value | value | value | value | value |
style · Property | numberStyle | format | format | format | format |
currency · Property | currency | format | format | format | format |
unit · Property | unit | format | format | format | format |
notation · Property | notation | format | format | format | format |
fractionDigits · Property | fractionDigits | format | format | format | format |
signDisplay · Property | signDisplay | format | format | format | format |
locale · Property | locale | locale | locale | locale | locale |
trend · Property | trend | trend | trend | trend | trend |
animation · Property | animation | animation | animation | animation | animation |
startValue · Property | startValue | startValue | startValue | startValue | startValue |
duration · Property | duration | duration | duration | duration | duration |
live · Property | live | live | live | live | live |
label · Property | label | label | label | label | label |
settle · Event | settle | onSettle | onSettle | onSettle | onSettle |
| Notes | <tanrei-number-ticker value number-style currency unit notation fraction-digits sign-display locale trend animation start-value duration live label>; style is spelled numberStyle (attribute number-style) because style is every element's own. Intl.NumberFormat(…).formatToParts gives the characters; each digit place is an inline-block column moved by transform: translateY() through the Web Animations API, and a retarget reads the drawn position from getComputedStyle first (NTK-6). The width moves with the shared size transition primitive. The text of NTK-9 is a visually hidden span; the drawn number is aria-hidden. The first view of NTK-8 is an IntersectionObserver. The characters are laid out as flex items in the locale's direction, the digits and their separators in one left-to-right run (NTK-13). A change of an ancestor's lang is seen by one MutationObserver shared by every ticker (NTK-14). | The six format props are one FloatingPointFormatStyle value (.number, .percent, .currency(code:), .measurement, with .notation(.compactName), .precision, .sign(strategy:)); locale is the environment's unless given. contentTransition(.numericText(countsDown:)) is not used: it cannot follow the trend rule of NTK-3 or the retarget of NTK-6. | The six format props are one TanreiNumberFormat value built on ICU's NumberFormatter (android.icu.number). Each digit column is an Animatable offset; liveRegion = LiveRegionMode.Polite is set on a node whose text changes only at settle. | The six format props are one NumberFormat of the intl package. Semantics(liveRegion:) on a node whose label changes only at settle. | The six format props are one format: Intl.NumberFormatOptions (Hermes ships Intl.NumberFormat). accessibilityLiveRegion="polite" on Android and AccessibilityInfo.announceForAccessibility on iOS, at settle only. |
Tokens
| Token | Aliases | Resolved (light) |
|---|---|---|
--tanrei-comp-number-ticker-animation | — | 0 |
--tanrei-comp-number-ticker-blur-slide-distance | sys.space.space100 | 8px |
--tanrei-comp-number-ticker-blur-radius | sys.space.space100 | 8px |
--tanrei-comp-number-ticker-motion-duration | sys.motion.role.resize.large | 400ms |
--tanrei-comp-number-ticker-motion-easing | sys.motion.easing.spatial | cubic-bezier(0.2, 0, 0, 1) |
--tanrei-comp-number-ticker-motion-reduced-duration | sys.motion.role.reduced | 100ms |
--tanrei-comp-number-ticker-motion-stagger | sys.motion.duration.short1 | 50ms |
Fixtures
Canonical renderings. Every platform snapshots each fixture under the same id so the results can be compared.
default
value: 1234 currency-ja
value: 1234 style: currency currency: JPY locale: ja-JP percent
value: 0.426 style: percent fractionDigits: 1 compact
value: 1250000 notation: compact locale: en-US signed
value: -12 signDisplay: except-zero arabic-digits
value: 1234 locale: ar-EG rtl
value: 1234 style: currency currency: EUR locale: he-IL direction: rtl Generated from specs/number-ticker.spec.json, tokens/comp/number-ticker.tokens.json, design/tokens/
Use a number ticker for a number that changes while a person looks at it, where the change itself is worth seeing: a count that goes up as orders arrive, a price that moves, a score, the figures of a dashboard that rise to their values when the page opens. The motion shows that the number changed, which way, and roughly by how much.
A number that changes rarely, or that nobody watches change, is plain text. A level in a known range — storage used of a quota — is a meter. Times and dates are not numbers: write them with the platform’s date and time formatting.
The ticker has no words and no number rules of its own. The platform’s number formatter writes it in the reader’s language: the group and decimal separators, the currency symbol, the percent sign, the short form of a large number (1.2K, 1.2万), and the digits themselves (١٢٣٤ in Arabic as Egypt writes it). Choose a style (decimal, percent, currency or unit), a currency code or a unit, compact notation, a fixed number of fraction digits and when to write a sign; the ticker takes the language of where it stands unless you give one.
It has no font, size or color either: it is drawn in the text style of where you place it, in figures of equal width so that the number does not shift as its digits change. It can be the large figure of a dashboard card or a count inside a sentence.
| Animation | Use for |
|---|---|
| Slide | Most numbers. Each changed digit’s column rolls to its new digit. The default system’s choice. |
| Blur | A quieter change: the old digit blurs out as the new one comes into focus. |
| Blur slide | The same, with the digits moving a short way in the direction of the change. |
| Flip | A split-flap board: departures, a countdown, a product whose look is mechanical. |
| None | A number that must change at once. |
Keep one animation across your product: set it once for the design system (comp.number-ticker.animation) rather than on each ticker.
By default every changed digit moves the way the whole number moved: up when it grew, down when it shrank, so that 19 to 20 moves both digits up. That reads as one change of one number. Choose digit when each place means something by itself — each digit then moves by its own change, so the ones go down from 9 to 0. up and down force one way, for a number that only ever counts one way.
- Place it in text, or give its container the text style you want it in. It takes everything from there.
- Give a label when nothing visible beside the number says what it is: “Revenue”, “Orders”.
- Leave live off for figures that change on their own. Turn it on only for a number the person is waiting for or changing.
- Use the start value on a dashboard so its figures rise once, the first time they are seen.
- Don’t color a rise green or a fall red through the ticker: it has no such colors. If a change means something, say it beside the number — a tag, a word, an arrow with a label.
- Don’t update a number many times a second. Each change takes the motion’s duration; a stream of changes reads as noise. Update it at the pace a person can follow.
- Don’t use it for time. A clock’s digits roll over at 59, not at 9.
- Role
none (text)- Labeling
- Read as one text: label, then the number as the formatter writes it. The drawn digits are hidden. With live polite, the settled value is told once per change.
- Minimum target
- The hit area meets the minimum target size even when the visual size is smaller. minimum 32px · pointer 44px · spacing 8px · touch 48px
Keyboard
| Keys | Action |
|---|
Notes
- Not interactive: no focus, no input, no target; minimumTarget holds trivially.
- Live regions: a number that is not the point of the moment is told nothing (off); one a person waits for is told politely once it settles, never each value it passes through.
- Pause, Stop, Hide (WCAG 2.2.2): one change's motion ends well within five seconds. A number the product updates by itself, again and again, alongside other content is auto-updating content: the product gives the means to pause the updates, or to set how often they come.
- Animation from interactions (WCAG 2.3.3): where motion is reduced, the number changes at once (NTK-7).
Generated from specs/number-ticker.spec.json, tokens/sys/measure.tokens.json
- Assistive technology reads one text: the label, then the number as the formatter writes it. The drawn digits are hidden, so the number is never read digit by digit or as the digits passing through their windows.
- By default nothing is announced: most figures are not the point of the moment. With live set to polite, the number is announced politely once each change has settled, never a value it passes through and never one a later change replaced.
- When reduced motion is requested, the new number is there at once, the old one fading out briefly.
- It takes the language and the direction of where it stands, and writes the number again at once when either changes.
- An unknown animation, trend, style, notation, sign display or live value, a duration that is not positive, a currency or unit the formatter does not know and a value that is not a number are reported in debug builds.
- If your product updates a number by itself again and again next to other content, give people a way to pause the updates or to choose how often they come (WCAG 2.2.2 Pause, Stop, Hide).
- Say what a change means in words where it matters. The motion shows that it changed; it does not say whether that is good or bad.