useRoll

A readout that rolls to a new value instead of swapping it: each digit steps through the ones in between, all together, fast when it's far and slowest on the last step. It's the drum SplitFlap turns on, and what roll does on LcdChip, StatTile and NumberField. useRoll(text, options) returns the text to draw, which is in between values while it rolls, so draw it aria-hidden and give the real value to assistive technology.

Feel Numbers that travel to their value, so you can see how far it moved and which way.

216rps

Requests

18Floor

Floor

Or let the agent fetch it: get_component("roll") on the Echo MCP server.

Installation

npx echo-ui-cli add roll

First time? Run npx echo-ui-cli init once — it sets the project up, and add refuses to run before it.

At a glance

Version: 0.3.0
Weight: 749 B · 859 B with what it imports (minified and gzipped; React not counted)
Reduced motion: It returns the value itself: no steps.

Usage

tsx

import { useRoll } from "@/echo/roll";

const shown = useRoll(String(count));

Composition

useRoll → the text to draw, one step at a time

Examples

A count

Draw what it returns; say the real value.

tsx

const shown = useRoll(String(count));
<span aria-hidden="true">{shown}</span>

Letters

Any drum: here a departures board's.

tsx

const shown = useRoll(gate, { drum: CHARS });

Accessibility

What it returns is in between values while it rolls: draw it aria-hidden and give the real value to assistive technology, the way LcdChip, StatTile and NumberField do.
It never announces anything by itself.

Tested against WCAG 2.2 AA on every release:

axe — No axe violations, in the component's own gallery and on its page.
keyboard — Every action is reachable and operable from the keyboard alone.
focus-visible — Focus is visible on every focusable part, in normal and forced-colors mode.
forced-colors — State stays visible when the look's colours are replaced by the system's.
target-size — Every target's real hit area is at least 24×24px, at every density.
reflow — Content reflows into 320px and survives a doubled text size.

Not covered: screen-reader: not yet verified by a person. Everything above is a machine check; a person has not yet driven this component with a screen reader.

Motion & sound

Reduced motion: It returns the value itself: no steps.

Props

useRoll props
Prop	Type	Default
`drum`The characters in order, each one a step. Defaults to the digits.	`string`
`enabled`Roll at all. false swaps the value outright. Default true.	`boolean`
`onTurn`Called on every step, for a tick.	`function`

Anti-patterns

Never roll a value that changes many times a second: each step is 55–120ms, so it falls behind by design.
Never roll text the user is typing: it's theirs, and it should appear as typed.

Changelog

v0.3.0 · 2026-10-12 · ChangedEvery item needs echo-ui-core 0.3.0 (all components). The drawn device, readability past AA and the design tests live in core, and the components that use them are built against it, so each item now declares echo-ui-core >=0.3.0 <0.4.0. Update core with the items: npm install echo-ui-core@^0.3.0 (or your package manager's), then npx echo-ui-cli update. An item whose files didn't change is the same code under a new version; the 0.2.0 files stay published.
v0.2.0 · 2026-10-04 · AddedDigits that roll: roll on LcdChip, StatTile and NumberField, and the useRoll hook under them. Pass roll and a new value steps each digit through the ones in between, all together, fast when it's far and slowest on the last step: 18 → 21 shows 29, 20, 21. A falling number rolls back, 99 → 100 turns the nines over and puts a 1 in front, and anything that isn't a digit (a comma, a colon) swaps at once. The digits in between are drawn but hidden from assistive technology, so the value is still read once, as it is; under reduced motion it doesn't roll. On NumberField it replaces the slide a step used to give the whole number, and typing never rolls. It's off by default, so nothing changes until you pass it. SplitFlap now turns on the same drum (echo-roll, which each of these installs with it); it looks and sounds the same.
v0.2.0 · 2026-10-04 · ChangedComments only, no behaviour change. Comments in the component source used to cite documents, milestones and ticket numbers from Echo's own planning, none of which exist in your project. The citations are gone and the sentences around them stay. Where a comment was only a citation, it now says what it meant. Three development warnings (HardwareButton's engraved/caption checks and StatusDot's missing-label check) also dropped the ticket code at the end of the message. echo-ui diff will show changes in most items; none of them are to code.
v0.2.0 · 2026-10-04 · ChangedAn item's version is now a function of declared data, not of how the changelog is formatted. The version an item ships under is published once and never rewritten, and it used to be inferred from prose: a regex for a bolded "Breaking" run across the whole unreleased section, and attribution by "does a bullet mention this name in backticks". One breaking entry therefore moved every item that changed that cycle, and an entry explaining that "Menu and Sheet are unchanged here" filed itself as a change to Menu and Sheet — which it really had.
v0.2.0 · 2026-10-04 · ChangedThe agent brief says Echo has not shipped. llms.txt and the MCP server's instructions led with npx echo-ui-cli init, and that name on npm is a reserved stub with no executable — so a model following the brief wrote an install step that fails with npx's own error. The brief now opens with the caveat, and the docs carry it on every surface that shows a command. One switch (CLI_RELEASED) silences all of them at launch, and a test refuses to let one move without the others. Affects all components only in what the brief says about installing them; no item's props, CSS or rendered semantics change.
v0.2.0 · 2026-10-04 · ChangedEcho's home is echo-ui.com. The registry, the docs and the packages all move to it from echo.nawwara.studio. Nothing was published under the old host, so no echo.json anywhere points at it and there is nothing to migrate — this is the last release where that is true.
v0.2.0 · 2026-10-04 · ChangedWeights, line heights, letter-spacing, z-index, border widths and icon sizes come from the theme scales in all components, with the old value as a fallback, so components keep working with echo-ui-core@0.0.1. Strays moved to the nearest step: most by under a pixel; HardwareButton icons are 14/16/20px (were 15/17/19).
v0.2.0 · 2026-10-04 · FixedContent now reflows into a 320px screen (400% zoom) and survives a doubled browser text size (WCAG 1.4.10, 1.4.4), across all components. Select's 180px floor, NumberField's readout, Segmented and Steps as flex items, EmptyState's grid columns, and Avatar's fixed-pixel disc all gave way; Panel counts its padding inside a width you set (box-sizing: border-box), so a <Panel style={{ width: 220 }}> is now 220px wide overall rather than 260px.

Preview