Money input

In FORMA

• Liegt in kit/arc/money-input und ist über @/forma/arc/money-input/money-input erreichbar.
• Farbe, Ecken, Höhen, Abstände, Tiefe, Schrift und Tempo kommen aus der Richtung (core/arc-bridge.ts); Arc behält Verhalten, Tastatur und Federn.

When to use

• Payment, tip, transfer, or budget amounts entered by hand.
• Invoice and expense forms where the currency may change.
• Amount fields that benefit from quick add chips such as +$10.

When not to use

• Use number-field for quantities and non currency numbers.
• Use slider or price-ladder when people pick from a range rather than type.
• Use scrub-input for design tool style drag adjustments.

Usage

import { useState } from "react";
import { MoneyInput } from "@/forma/arc/money-input/money-input";

export function TipAmount() {
  const [cents, setCents] = useState<number | null>(1500);
  return (
    <MoneyInput
      label="Amount"
      name="amount"
      value={cents}
      onValueChange={setCents}
      currencies={["USD"]}
      min={100}
      max={100_000}
      quickAdd={[5, 10, 20]}
    />
  );
}

API reference

MoneyInput

A currency amount field that groups digits as you type, holds missing cents as ghosts, scales long amounts to fit, and returns minor units.

Keyboard interactions

Accessibility

• The input has role="spinbutton" with aria-valuenow in major units, aria-valuetext as the full currency string, and min and max when set.
• The animated digits are aria-hidden; the real input carries the value, so screen readers and autofill see plain text.
• The range, hint, and error are linked with aria-describedby; limits, chip adds, and currency changes are announced politely.
• The currency menu is a listbox with aria-activedescendant and typeahead.

Motion

• Chips and arrow keys roll each digit column in the direction of change while new columns open their width; typing cuts straight to the result so the caret never lags.
• A refused change kicks the amount sideways on a bouncy spring and flashes the range.
• The currency symbol swaps with a short roll while its slot springs to the new width; long amounts scale down to fit on a spring.
• Reduced motion removes the rolls, kick, and width springs; digits fade and sizes jump.

Responsive behavior

• Under 420px viewport width the amount text drops a size and the padding tightens.
• A ResizeObserver scales the amount down to fit its box instead of scrolling, so long numbers stay readable on phones.
• inputMode is decimal (numeric for zero decimal currencies like JPY), which brings up the number keypad on touch.

Performance

• Intl.NumberFormat instances are cached per locale and currency.
• Each digit is its own animated column; amounts are capped at 12 integer digits, which keeps the column count small.

Notes for AI

• Store the value in minor units (integers) to avoid floating point errors; details.major and details.formatted are for display.
• Use for money only. For plain numbers with units use number-field, and for drag-to-adjust values use scrub-input.
• Pass one code in currencies to lock the currency; the code then shows as static text.
• max refuses typing past it; min is only checked on blur, so people can type through smaller amounts on the way.

Related

• Number field: Enter a bounded number with clear increment controls.
• Scrub input: A Figma-style number field: drag the label to scrub, or type values, units, and arithmetic.
• Input: A single line field with clear labels and useful states.
• Pricing calculator: A seat slider and billing toggle drive plan cards with rolling prices and a moving recommended badge.
• Invoice studio: An editable invoice with live totals and a clear save flow.

Also in special inputs

• Phone input: A phone field with a country picker, formatting as you type, and E.164 output.
• Tag input: Turn short text values into removable tags.
• Mention input: A textarea with @people and #channel mentions that act as single tokens, with suggestions at the caret.
• Shortcut recorder: Record key combinations into key caps, with conflict warnings, Kbd, and a searchable cheatsheet.

Guidance for AI tools

Money input: A currency field with live grouping, stable width, rolling digits, and minor-unit output. Follow the declared prop types and do not invent props. Keep keyboard access, reduced motion support, and both light and dark themes intact when adapting it.

Full library index: https://uiarc.dev/llms.txt