Basic Example
RollingNumber displays changing numeric values with a smooth per-digit roll animation and optional color pulse. It supports full Intl.NumberFormat options, custom typography, ReactNode prefixes/suffixes, and accessibility.
Pass a number in the value prop. Use the format prop for Intl formatting (currency, percent, grouping, compact) instead of pre-formatting the string yourself.
function Example() {
const values = [12345.67, 123340.011, 1220340.0123];
const [valIdx, setValIdx] = useState(0);
return (
<VStack gap={3}>
<RollingNumber value={values[valIdx]} font="display3" />
<Button
onClick={() => {
setValIdx((prev) => (prev + 1) % values.length);
}}
alignSelf="flex-start"
>
Next
</Button>
</VStack>
);
}
Example Use Case
function Examples() {
const [price, setPrice] = useState<number>(12345.67);
const [difference, setDifference] = useState<number>(0);
const onNext = () =>
setPrice((p) => {
const delta = (Math.random() - 0.5) * 200;
const next = Math.max(0, p + delta);
const newPrice = Math.round(next * 100) / 100;
setDifference(newPrice - p);
return newPrice;
});
const trendColor = difference >= 0 ? 'fgPositive' : 'fgNegative';
return (
<VStack gap={2}>
<Text font="label1">Portfolio Balance</Text>
<RollingNumber
colorPulseOnUpdate
font="display3"
format={{ style: 'currency', currency: 'USD' }}
value={price}
/>
<HStack alignItems="center">
<RollingNumber
accessibilityLabelPrefix={difference > 0 ? 'up ' : difference < 0 ? 'down ' : ''}
color={trendColor}
font="body"
format={{
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2,
maximumFractionDigits: 2,
}}
prefix={
difference >= 0 ? (
<Icon color={trendColor} name="diagonalUpArrow" size="xs" />
) : (
<Icon color={trendColor} name="diagonalDownArrow" size="xs" />
)
}
styles={{
prefix: {
paddingRight: 'var(--space-1)',
},
}}
suffix={`(${((Math.abs(difference) / price) * 100).toFixed(2)}%)`}
value={Math.abs(difference)}
/>
</HStack>
<Text font="label1">BTC Conversion</Text>
<HStack alignItems="center" gap={1}>
<Icon color="fgPrimary" name="arrowsVertical" size="xs" testID="swap-icon" />
<RollingNumber
color="fgPrimary"
fontFamily="body"
fontSize="body"
fontWeight="body"
format={{ minimumFractionDigits: 8, maximumFractionDigits: 8 }}
value={price / 150_000}
/>
</HStack>
<Button alignSelf="flex-start" onClick={onNext}>
Next
</Button>
</VStack>
);
}
Use format prop for currency, percent, grouping, and compact notation formatting. The format prop takes in Intl.NumberFormat options.
function Example() {
const [value, setValue] = React.useState(92345.67);
const onNext = () => setValue((v) => v * 13.5);
return (
<VStack gap={2}>
<Text as="p" display="block" font="label1">
Compact number with currency sign
</Text>
<h1>
<RollingNumber
font="display1"
format={{
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2,
maximumFractionDigits: 2,
notation: 'compact',
}}
value={value}
/>
</h1>
<Button alignSelf="flex-start" onClick={onNext}>
Next
</Button>
<Text as="p" display="block" font="label1">
Number without grouping
</Text>
<RollingNumber
font="display1"
format={{
useGrouping: false,
}}
value={92345.67}
/>
</VStack>
);
}
Typography
RollingNumber forwards all Text props, but only character-level typographic props (e.g., font, fontFamily, fontSize, fontWeight, lineHeight, tabularNumbers, color) are meaningful for its per-digit rendering. Layout/container props may have no effect—use them judiciously.
function Example() {
const [price, setPrice] = React.useState(9876.54);
const onNext = () =>
setPrice((p) => Math.max(0, Math.round((p + (Math.random() - 0.5) * 100) * 100) / 100));
return (
<VStack gap={2}>
<Text as="p" display="block" font="label1">
Font sizes, weights, and line heights
</Text>
<RollingNumber
fontSize="display3"
fontWeight="title3"
value={price}
format={{ style: 'currency', currency: 'USD' }}
/>
<RollingNumber
fontSize="title3"
fontWeight="headline"
value={price}
format={{ style: 'currency', currency: 'USD' }}
/>
<RollingNumber
fontSize="body"
fontWeight="body"
lineHeight="display3"
value={price}
format={{ style: 'currency', currency: 'USD' }}
/>
<Text as="p" display="block" font="label1">
Responsive font (phone, tablet, desktop)
</Text>
<RollingNumber
font={{ phone: 'body', tablet: 'title3', desktop: 'display3' }}
format={{ style: 'currency', currency: 'USD' }}
value={price}
/>
<Text as="p" display="block" font="label1">
Tabular numbers vs non-tabular
</Text>
<RollingNumber
font="display3"
format={{ style: 'currency', currency: 'USD' }}
value={price}
/>
<RollingNumber
tabularNumbers={false}
font="display3"
format={{ style: 'currency', currency: 'USD' }}
value={price}
/>
<Button alignSelf="flex-start" onClick={onNext}>
Next
</Button>
</VStack>
);
}
AlignmentKeep tabularNumbers enabled (default) to avoid horizontal width shifting as digits change.
Color and Transition
Customize color and motion. Configure y to control the digit roll, and color for the pulse.
transition prop
- Type:
{ y?: Transition; color?: Transition } (framer-motion Transition)
- Optional
type: 'tween' | 'spring' | 'inertia'; defaults to 'tween' if not provided
- Default:
{ y: { duration: durations.moderate3 / 1000, ease: curves.global }, color: { duration: durations.slow4 / 1000, ease: curves.global } }
function Example() {
const [price, setPrice] = React.useState(555.55);
const onNext = () =>
setPrice((p) => Math.max(0, Math.round((p + (Math.random() - 0.5) * 50) * 100) / 100));
return (
<VStack gap={2}>
<Text as="p" display="block" font="label1">
Color pulse and custom transition
</Text>
<RollingNumber
colorPulseOnUpdate
font="title1"
format={{ style: 'currency', currency: 'USD' }}
transition={{
color: { duration: 0.3, ease: 'easeInOut' },
y: { duration: 0.3, ease: 'easeIn' },
}}
value={price}
/>
<RollingNumber
colorPulseOnUpdate
color="accentBoldBlue"
font="title1"
format={{ style: 'currency', currency: 'USD' }}
transition={{
color: { duration: 1.2, ease: 'easeInOut' },
y: { duration: 1.2, ease: 'easeIn' },
}}
value={price}
/>
<Text as="p" display="block" font="label1">
Customize positive and negative change colors
</Text>
<RollingNumber
colorPulseOnUpdate
font="title1"
negativePulseColor="bgWarning"
positivePulseColor="fgPrimary"
value={price}
/>
<Text as="p" display="block" font="label1">
Fast digits, slow color
</Text>
<RollingNumber
colorPulseOnUpdate
font="title1"
format={{ style: 'currency', currency: 'USD' }}
transition={{
y: { duration: 0.1, ease: 'easeIn' },
color: { duration: 1.2, ease: 'easeInOut' },
}}
value={price}
/>
<Text as="p" display="block" font="label1">
Springy digits
</Text>
<RollingNumber
colorPulseOnUpdate
font="title1"
format={{ style: 'currency', currency: 'USD' }}
transition={{
y: {
type: 'spring',
stiffness: 1000,
damping: 24,
mass: 3,
},
}}
value={price}
/>
<Text as="p" display="block" font="label1">
Custom easings
</Text>
<RollingNumber
colorPulseOnUpdate
font="title1"
format={{ style: 'currency', currency: 'USD' }}
transition={{
y: { duration: 0.25, ease: 'easeOut' },
color: { duration: 0.5, ease: 'easeInOut' },
}}
value={price}
/>
<Button alignSelf="flex-start" onClick={onNext}>
Next
</Button>
</VStack>
);
}
Prefix and Suffix
Attach text or React nodes before/after the number to create rich compositions. If the prefix/suffix is a string, it will pulse color together with the main number.
function Example() {
const values = [98345.67, 91345.67, 123450.123, 1234512.88];
const textPrefixes = ['+', '-', ''];
const textSuffixes = [' BTC', ' ETH', ''];
const iconPrefixes = [
<Icon key="arrowUp" name="arrowUp" size="l" />,
<Icon key="arrowDown" name="arrowDown" size="l" />,
null,
];
const iconSuffixes = [
<Icon key="arrowDown" name="arrowDown" size="l" />,
<Icon key="arrowUp" name="arrowUp" size="l" />,
null,
];
const [idx, setIdx] = React.useState(0);
const onNext = () => setIdx((i) => (i + 1) % values.length);
const value = values[idx];
const format = {
style: 'currency' as const,
currency: 'USD',
minimumFractionDigits: 2,
maximumFractionDigits: 5,
};
return (
<VStack gap={2}>
<Text as="p" display="block" font="label1">
Simple text prefix and suffix
</Text>
<RollingNumber
colorPulseOnUpdate
font="display1"
format={format}
prefix={textPrefixes[idx]}
suffix={textSuffixes[idx]}
value={value}
/>
<Text as="p" display="block" font="label1">
ReactNode prefix and suffix
</Text>
<RollingNumber
colorPulseOnUpdate
font="display1"
format={format}
prefix={iconPrefixes[idx]}
suffix={iconSuffixes[idx]}
value={value}
/>
<Button alignSelf="flex-start" onClick={onNext}>
Next
</Button>
</VStack>
);
}
function SubscriptionPriceExample() {
const [yearly, setYearly] = React.useState(false);
const price = yearly ? 199 : 19;
const suffix = yearly ? '/yr' : '/mo';
return (
<VStack gap={1}>
<RollingNumber
colorPulseOnUpdate
accessibilityLabel={`$${price} ${suffix === '/yr' ? 'yearly' : 'monthly'}`}
font="display1"
format={{
style: 'currency',
currency: 'USD',
minimumFractionDigits: 0,
maximumFractionDigits: 0,
}}
styles={{
suffix: {
position: 'relative',
top: 'var(--space-1_5)',
color: 'var(--color-fgMuted)',
fontSize: 'var(--fontSize-title1)',
},
}}
suffix={suffix}
transition={{
y: { type: 'spring', stiffness: 80, damping: 24, mass: 3 },
}}
value={price}
/>
<Button alignSelf="flex-start" onClick={() => setYearly((v) => !v)}>
{yearly ? 'Switch to monthly' : 'Switch to yearly'}
</Button>
</VStack>
);
}
AccessibilityWhen using React nodes for prefix/suffix, provide an accessibilityLabel or use accessibilityLabelPrefix/accessibilityLabelSuffix so screen readers announce a descriptive string.
Style Overrides
Customize the look of each logical section (i18nPrefix, integer, fraction, i18nSuffix, prefix, suffix).
function Example() {
const [price, setPrice] = React.useState(12345.67);
const onNext = () => {
setPrice((p) => Math.max(0, Math.round((p + (Math.random() - 0.5) * 200) * 100) / 100));
};
return (
<VStack gap={2}>
<Text as="p" display="block" font="label1">
Customize per-section styles
</Text>
<RollingNumber
colorPulseOnUpdate
font="display1"
format={{
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2,
notation: 'compact',
}}
prefix="-"
styles={{
root: {
border: '1px dashed var(--color-bgLine)',
padding: '4px 8px',
borderRadius: 8,
background: 'var(--color-bgSecondaryWash)',
},
i18nPrefix: { color: 'var(--color-accentBoldBlue)' },
prefix: { color: 'var(--color-accentBoldPurple)' },
integer: { letterSpacing: '-1px' },
fraction: { opacity: 0.2, letterSpacing: '10px' },
i18nSuffix: { color: 'var(--color-fgMuted)' },
suffix: { color: 'var(--color-accentBoldYellow)', marginLeft: 10 },
}}
suffix="BTC"
value={price}
/>
<Button alignSelf="flex-start" onClick={onNext}>
Next
</Button>
</VStack>
);
}
Subscript Notation for Tiny Decimals
Enable enableSubscriptNotation to compactly represent leading zeros in the fractional part.
function Example() {
const values = [0.0000000001, 0.00009, 0.000012, 0.0000001, 0.000000000000000000000011];
const [idx, setIdx] = React.useState(0);
const value = values[idx];
const format = { minimumFractionDigits: 2, maximumFractionDigits: 25 };
return (
<VStack gap={1}>
<Text as="p" display="block" font="label1">
Subscript examples
</Text>
<Text as="span" display="block" font="label2">
Default:
</Text>
<RollingNumber font="display3" format={format} value={value} />
<Text as="span" display="block" font="label2">
With subscript:
</Text>
{(['display1', 'title3', 'body'] as const).map((fontKey) => (
<RollingNumber
key={fontKey}
enableSubscriptNotation
font={fontKey}
format={format}
value={value}
/>
))}
<Button alignSelf="flex-start" onClick={() => setIdx((i) => (i + 1) % values.length)}>
Next
</Button>
</VStack>
);
}
You can also provide formattedValue, and the component will render formattedValue directly instead of using the internal formatter. The numeric value is still required to drive animations and color pulse.
function Example() {
const btcPrices = [
{ value: 98765.43, formattedValue: '¥98,765.43 BTC' },
{ value: 931.42, formattedValue: '$931.42 BTC' },
{ value: 100890.56, formattedValue: '¥100,890.56 BTC' },
{ value: 149432.12, formattedValue: '¥149,432.12 BTC' },
{ value: 150321.23, formattedValue: '¥150,321.23 BTC' },
];
const subscripts = [
{ value: 0.0000000001, formattedValue: '€0,0₉1', accessibilityLabel: '€0.0000000001' },
{ value: 0.00009, formattedValue: '€0,0₄9', accessibilityLabel: '€0.00009' },
{ value: 0.000012, formattedValue: '€0,0₄12', accessibilityLabel: '€0.000012' },
{ value: 0.0000001, formattedValue: '€0,0₆1', accessibilityLabel: '€0.0000001' },
{
value: 0.000000000000000000000011,
formattedValue: '€0,0₂₂11',
accessibilityLabel: '€0.000000000000000000000011',
},
];
const [idx, setIdx] = React.useState(0);
const onNext = () => setIdx((i) => (i + 1) % 5);
return (
<VStack gap={1}>
<Text as="p" display="block" font="label1">
User-provided formatted value
</Text>
<Text as="p" display="block" font="label2">
BTC prices
</Text>
<RollingNumber
colorPulseOnUpdate
font="display3"
formattedValue={btcPrices[idx].formattedValue}
prefix={<Icon name="crypto" size="l" />}
value={btcPrices[idx].value}
/>
<Text as="p" display="block" font="label2">
Subscripts with a comma as the decimal separator
</Text>
<RollingNumber
colorPulseOnUpdate
accessibilityLabel={subscripts[idx].accessibilityLabel}
font="display3"
formattedValue={subscripts[idx].formattedValue}
value={subscripts[idx].value}
/>
<Button alignSelf="flex-start" onClick={onNext}>
Next
</Button>
</VStack>
);
}
Accessibility and formattedValueWhen you provide formattedValue, the accessibilityLabel will default to your formattedValue. However, what’s rendered on screen is not always ideal for accessibility. For example, the subscript notation '0₉' may be announced as '09'. Provide your own accessibilityLabel as needed.
Patterns & Recipes
Practical demos combining formatting, animation, and interactivity.
Counter
function CounterExample() {
const [count, setCount] = React.useState(0);
return (
<VStack gap={1}>
<HStack alignItems="center" gap={2}>
<IconButton name="minus" onClick={() => setCount((c) => Math.max(0, c - 1))} />
<RollingNumber
colorPulseOnUpdate
font="display1"
format={{ minimumFractionDigits: 0, maximumFractionDigits: 0 }}
value={count}
/>
<IconButton name="add" onClick={() => setCount((c) => c + 1)} />
</HStack>
</VStack>
);
}
Countdown
function CountDownExample() {
const pad = (n: number) => String(n).padStart(2, '0');
const totalSeconds = 5 * 60;
const [seconds, setSeconds] = React.useState(totalSeconds);
const [running, setRunning] = React.useState(false);
React.useEffect(() => {
if (!running) return;
const id = setInterval(() => {
setSeconds((prev) => {
if (prev <= 1) {
clearInterval(id);
return 0;
}
return prev - 1;
});
}, 1000);
return () => clearInterval(id);
}, [running]);
const minutes = Math.floor(seconds / 60);
const secs = seconds % 60;
const formatted = `${pad(minutes)}:${pad(secs)}`;
const onReset = () => setSeconds(totalSeconds);
const progress = Math.max(0, Math.min(1, (totalSeconds - seconds) / totalSeconds));
return (
<VStack gap={1}>
<RollingNumber font="display3" formattedValue={formatted} value={seconds} ariaLive="off" />
<HStack gap={2}>
<Button onClick={() => setRunning((r) => !r)}>{running ? 'Pause' : 'Start'}</Button>
<Button onClick={onReset}>Reset</Button>
</HStack>
<Text font="label1">Countdown with percent</Text>
<VStack gap={1}>
<ProgressBar progress={progress} />
<RollingNumber
font="body"
format={{ style: 'percent', maximumFractionDigits: 0 }}
prefix="Elapsed: "
value={progress}
ariaLive="off"
/>
</VStack>
</VStack>
);
}
Live Auction
function LiveBiddingExample() {
const [currentBid, setCurrentBid] = useState(45000);
const [bidCount, setBidCount] = useState(23);
const [timeLeft, setTimeLeft] = useState(180);
React.useEffect(() => {
const timer = setInterval(() => {
setTimeLeft((t) => Math.max(0, t - 1));
}, 1000);
return () => clearInterval(timer);
}, []);
const placeBid = (increment: number) => {
setCurrentBid((b) => b + increment);
setBidCount((c) => c + 1);
};
const minutes = Math.floor(timeLeft / 60);
const seconds = timeLeft % 60;
return (
<VStack gap={2}>
<VStack gap={1}>
<Text color="fgMuted" font="caption">
Current Bid
</Text>
<RollingNumber
colorPulseOnUpdate
font="display2"
format={{ style: 'currency', currency: 'USD', minimumFractionDigits: 0 }}
positivePulseColor="accentBoldRed"
transition={{
y: { type: 'spring', stiffness: 200, damping: 20 },
}}
value={currentBid}
/>
<HStack gap={1}>
<RollingNumber font="body" format={{ minimumFractionDigits: 0 }} value={bidCount} />
<Text font="body">bids placed</Text>
<Text color="fgMuted" font="body">
•
</Text>
<RollingNumber
color={timeLeft < 30 ? 'fgNegative' : 'fg'}
font="body"
formattedValue={`${minutes}:${String(seconds).padStart(2, '0')}`}
value={timeLeft}
ariaLive="off"
/>
<Text font="body">remaining</Text>
</HStack>
</VStack>
<HStack gap={1}>
<Button onClick={() => placeBid(100)}>+$100</Button>
<Button onClick={() => placeBid(500)}>+$500</Button>
<Button onClick={() => placeBid(1000)}>+$1000</Button>
</HStack>
</VStack>
);
}
function StatisticsExample() {
const [views, setViews] = useState(1234567);
const [likes, setLikes] = useState(89432);
const [shares, setShares] = useState(12789);
const [downloads, setDownloads] = useState(567890);
const simulateActivity = () => {
setViews((v) => v + Math.floor(Math.random() * 1000));
setLikes((l) => l + Math.floor(Math.random() * 200));
setShares((s) => s + Math.floor(Math.random() * 100));
setDownloads((d) => d + Math.floor(Math.random() * 500));
};
return (
<VStack gap={2}>
<HStack gap={4}>
<VStack alignItems="center" gap={0.5}>
<RollingNumber
colorPulseOnUpdate
font="title1"
format={{ notation: 'compact', maximumFractionDigits: 1, minimumFractionDigits: 1 }}
positivePulseColor="accentBoldBlue"
value={views}
/>
<Text color="fgMuted" font="caption">
Views
</Text>
</VStack>
<VStack alignItems="center" gap={0.5}>
<RollingNumber
colorPulseOnUpdate
font="title1"
format={{ notation: 'compact', maximumFractionDigits: 1, minimumFractionDigits: 1 }}
positivePulseColor="accentBoldRed"
prefix={<Icon color="accentBoldRed" name="heart" />}
styles={{ prefix: { paddingRight: 'var(--space-0_5)' } }}
value={likes}
/>
<Text color="fgMuted" font="caption">
Likes
</Text>
</VStack>
<VStack alignItems="center" gap={0.5}>
<RollingNumber
colorPulseOnUpdate
font="title1"
format={{ notation: 'compact', maximumFractionDigits: 1, minimumFractionDigits: 1 }}
positivePulseColor="accentBoldGreen"
value={shares}
/>
<Text color="fgMuted" font="caption">
Shares
</Text>
</VStack>
<VStack alignItems="center" gap={0.5}>
<RollingNumber
colorPulseOnUpdate
font="title1"
format={{ notation: 'compact', maximumFractionDigits: 1, minimumFractionDigits: 1 }}
positivePulseColor="accentBoldPurple"
value={downloads}
/>
<Text color="fgMuted" font="caption">
Downloads
</Text>
</VStack>
</HStack>
<Button alignSelf="flex-start" onClick={simulateActivity}>
Simulate Activity
</Button>
</VStack>
);
}
Anatomy & Customization
RollingNumber is composed of small, swappable subcomponents and exposes granular className/style hooks for each section of the number. Use these to customize structure and styling or to plug in your own components.
Subcomponents
- RollingNumberMaskComponent: Component used to mask the animated digit content.
- RollingNumberAffixSectionComponent: Component used to render ReactNode
prefix / suffix props.
- RollingNumberValueSectionComponent: Component used to render the four
Intl.NumberFormat sections (i18nPrefix, integer, fraction, i18nSuffix).
- RollingNumberDigitComponent: Component used to render the per-digit roll animation.
- RollingNumberSymbolComponent: Component used to render non-digit symbols (group separators, decimal, literals, etc.).
You can replace any of these with your own components via props:
<RollingNumber
RollingNumberMaskComponent={MyMask}
RollingNumberAffixSectionComponent={MyAffixSection}
RollingNumberValueSectionComponent={MyValueSection}
RollingNumberDigitComponent={MyDigit}
RollingNumberSymbolComponent={MySymbol}
value={1234.56}
format={{ style: 'currency', currency: 'USD' }}
/>
Class name overrides
Use classNames to target specific parts for CSS styling (Linaria or your own classes):
- root: Outer container (
Text root)
- visibleContent: Motion-wrapped span containing the visible number (color animation lives here)
- formattedValueSection: Container around the four i18n sections
- i18nPrefix: Section generated by
Intl.NumberFormat before the number
- integer: Integer part of the number
- fraction: Fractional part of the number
- i18nSuffix: Section generated by
Intl.NumberFormat after the number
- prefix: Wrapper around your
prefix prop
- suffix: Wrapper around your
suffix prop
- text:
Text element used for digits, separators, prefix, and suffix
Style overrides
Use styles to inline style specific parts:
- root, visibleContent, formattedValueSection, i18nPrefix, integer, fraction, i18nSuffix, prefix, suffix, text
styles.text applies to the shared Text component that renders digits, symbols, prefix, and suffix.
Structure diagrams
High-level anatomy of RollingNumber and its sections:
RollingNumber (root: Text)
├── screenReaderOnly <span aria-live> (hidden a11y text)
└── <m.span> (visibleContent)
├── AffixSection (prefix) ← your ReactNode prefix
├── HStack (formattedValueSection)
│ ├── ValueSection (i18nPrefix)
│ ├── ValueSection (integer)
│ ├── ValueSection (fraction)
│ └── ValueSection (i18nSuffix)
└── AffixSection (suffix) ← your ReactNode suffix
Per-digit rendering inside a ValueSection:
ValueSection
├── Symbol(s) (e.g., currency, group, decimal)
└── Digit(s)
└── Mask
└── DigitContainer (animated)
├── non-active digits above (positioned)
├── active digit (centered)
└── non-active digits below (positioned)