Number field

Overview

link

Web

tanrei-number-field

schedule

SwiftUI

TanreiNumberField

radio_button_unchecked

Jetpack Compose

TanreiNumberField

radio_button_unchecked

Flutter

TanreiNumberField

radio_button_unchecked

React Native

NumberField

radio_button_unchecked

Variants not shipped in

tanrei: filled, outlined

Generated from docs/status/status.json, specs/number-field.spec.json

A number field with a unit and limits, and one that holds an amount of money

Use a number field for a number that the product reads as a number: a quantity, a size, a percentage, an amount. People type it in the form of their locale, or step it with the arrow keys or the two buttons at the end of the field. The field is drawn and measured as the text field of the same variant and size.

Built from a field and a number input. The field is the frame: the label, the required or optional mark, the help and the error. The number input is the control: the box, the number, its unit and the two steppers. The number field draws nothing of its own and has no token: every property it has is a property of one of the two, given to it unchanged.

A number field is a field already: it is never placed inside a field. Where the label stands elsewhere — beside a slider, in a cell of a table — use the number input alone.

It is a block as wide as the place it is put in, and its box fills it. It has no width of its own: for a narrower field, give it a narrower place.

On the web it is <tanrei-number-field>. The other platforms have not implemented it yet.

Usage

link

value is a number, or null while the field holds none. It changes when the person commits — focus leaves the field, they press Enter, or they step — and not at every keystroke. While they type, the text is theirs: nothing is refused, reformatted, clamped or rounded. input carries what the text reads as meanwhile.

<form>
  <tanrei-number-field name="quantity" label="Quantity" value="1" min="1" max="99"
    required required-text="Required" invalid-text="Enter a number." increment-label="Increase" decrement-label="Decrease"></tanrei-number-field>
</form>

<!-- A unit, a step of a quarter, and no upper limit. -->
<tanrei-number-field id="radius" label="Corner radius" value="8" min="0" step="0.25" suffix-text="px" increment-label="Increase" decrement-label="Decrease"></tanrei-number-field>

<!-- Money: a sign before, a code after, always two decimals. -->
<tanrei-number-field label="Amount" value="120" prefix-text="$" suffix-text="USD"
  min-fraction-digits="2" max-fraction-digits="2" increment-label="Increase" decrement-label="Decrease"></tanrei-number-field>

<script type="module">
  import '@tanrei/web/components/number-field';

  const radius = document.querySelector('#radius');
  // A commit changed the value. It is already the new one: a number, or null.
  radius.addEventListener('change', () => save(radius.value));
  // The person is typing or stepping: the number the text reads as, not clamped and not rounded, or null.
  radius.addEventListener('input', (e) => preview(e.detail.value));
  // A text that is not a number was committed. The field keeps it and shows invalidText:
  // detail.text is that text, empty where the field was given none.
  radius.addEventListener('entryerror', (e) => console.log(e.detail.reason, e.detail.text));
</script>

import { NumberField } from '@tanrei/react';

<NumberField label="Corner radius" value={radius} min={0} step={0.25} suffixText="px"
  incrementLabel="Increase" decrementLabel="Decrease"
  onChange={(event) => setRadius(event.currentTarget.value)} />

One level down

link

The same field, written by hand from its two members, is the same picture, and to assistive technology the same spin button with the same name, description and states:

<tanrei-field label="Quantity" required required-text="Required"
  supporting-text="Up to 99 per order.">
  <tanrei-number-input name="quantity" min="1" max="99" invalid-text="Enter a number."
    increment-label="Increase" decrement-label="Decrease"></tanrei-number-input>
</tanrei-field>

The same field written by hand: a field with a number input in it

Go one level down when you need an arrangement the number field does not offer:

You need	Use
A label, the box, help and an error	The number field
Something of your own inside the frame, beside or below the box	A field with a number input and your own element in it
The box alone, under a label that stands elsewhere: beside a slider, a cell of a table, a toolbar	The number input alone, named by its own label

What changes one level down is where things are said. name, value, the limits and the unit are on the number input, which is then the control the form meets, and its events are heard on it. label, error, disabled and the requirement stay on the field, which passes them to the control: do not set the input’s own. There is nothing the number field does that the field and the number input written by hand do not do.

Specs

link

A stepper disabled at the limit, digits at the end edge, no steppers, an error, a read-only and a disabled number field

The field

link

Part	What it is
Label	The field’s: above the container (stacked). In filled and outlined the number input draws it, floating inside the box, and the field draws no label row. It is the accessible name, drawn or hidden with labelHidden
Requirement mark	The field’s, after the label: the requirement tag in its required form, an asterisk or nothing for required; the requirement tag in its optional form for optional. A floating label takes the asterisk
Input	The number input’s: the number as text. What the person typed while they edit; the committed number in the locale’s form otherwise. One line, which scrolls
Prefix, suffix	The number input’s: fixed text before and after the number, such as a currency sign or a unit. Part of the box, never of the value
Steppers	The number input’s: two buttons at the end, the first steps down, the second up. Leave them out with steppers false
Supporting text	The field’s: a line of help. While the field is in error the error text takes its place (below it, where the design system keeps both) — errorText while error is true, and invalidText while the text is not a number. It starts and ends at the box’s text padding, with and without steppers

The three variants and the three sizes, small (32), medium (40) and large (56), are the text field’s. The default system ships stacked only.

The number field has no token of its own. Its box reads the number input’s tokens, its rows read the field’s tokens, and its two steppers the Button’s, wherever they are set. To change one instance, set a member’s token on it: style="--tanrei-comp-field-label-gap: 0.75rem".

The two steppers are text Buttons of the medium size, side by side. Under the default system they take 88 of the field’s width, and each is a full touch target. They are never drawn smaller and never stacked: where a row cannot afford them, turn them off. The keys still step.

The value and the text

link

When	What happens
The person types, pastes or dictates	Nothing is changed. input carries the number the text reads as, or null
Focus leaves, or Enter	The text is committed: raised to min, lowered to max, rounded to maxFractionDigits, made the value, and written back in the locale’s form. change fires if the value differs
The text is empty	The value becomes null
The text is not a number	The text stays. The value becomes null, the field is in error and shows invalidText — its errorText where there is none — and entryerror fires
The product sets value	The number is shown, whatever was typed. No event fires, and the number is not corrected by min and max

A committed number is written with the locale’s digits and decimal separator, between minFractionDigits and maxFractionDigits digits after it, and without grouping separators — so what is shown can be typed back.

The same value, 1.5, in German and in Egyptian Arabic

A text is read leniently, by the field’s locale — or, where that is empty, by the language of the page:

• Spaces around the number and inside it are ignored.
• A hyphen-minus, a minus sign or a plus sign before the digits is the sign.
• ASCII digits, the locale’s own digits and full-width digits are all digits.
• The locale’s grouping separator is ignored between digits: 1,234.50 reads as 1234.5 in English.
• A typed or pasted prefix and suffix are ignored: 12 px reads as 12.
• Letters, an exponent, two separators or a sign alone are not a number.

The field never guesses between two locales. In German, where the comma is the decimal separator, 1.500 reads as 1500 and 1.5 as 15.

In a right-to-left layout: a unit in Latin letters after the number, from left to right, and a unit in the page's own script at the number's left

A number and its unit are one piece of writing. The prefix is written before the number and the suffix after it, in the direction of the unit’s own script, whatever the direction of the page. So “44 px”, “$ 120 USD” and “40 %” read in an Arabic or a Hebrew page as they do in an English one, and a unit written in Arabic or Hebrew letters stands at the number’s left. The steppers and the label follow the page. align="end" puts the number against its unit: at the right for a unit in Latin letters or signs, in both directions. For a Latin currency code at the number’s left, begin the suffix with a right-to-left mark (U+200F).

Stepping

link

Input	What happens
Up Arrow, Down Arrow	Steps by step
Page Up, Page Down	Steps by ten times step
A press on a stepper	Steps once. Held, it repeats: after half a second, then ten times a second, then twenty
Home, End, Left Arrow, Right Arrow	Move the caret in the text
The wheel, a drag	Nothing. The page scrolls

A step goes to the next number on the step’s grid, counted from min (from zero without one): with a step of 5, 12 steps up to 15 and down to 10. It is computed in decimal, so 0.2 stepped by 0.1 is 0.3. An empty field steps to the number nearest to zero that the limits allow.

step says how far a step goes. It does not limit what may be typed: with a step of 5, a typed 12 stays 12. To accept only some numbers, validate the value and set error.

With a slider

link

A number beside a slider, under one row title, is the box alone: a number input, named by its own label. Its page has the sample.

Anatomy

Anatomy

Drawn over the fixture stacked-empty, as the web package draws it.

Part	Description
1 field	The Field: the label row with its glyph and its requirement mark, and the supporting row with the help and the error text. In a look whose input floats the label it draws no label row.
2 number-input	The number input, as the Field's one control: the box, the number in it, the prefix and the suffix, the two steppers, and the label that floats in the box in the looks that float one.

Properties

Property	Type	Default	Description
variant	stacked | filled | outlined	"stacked"	The text input's three looks, so that a number input is drawn as the text inputs beside it: stacked is a filled box that shows focus and error with a line inside its edge and draws no label — the label of the Field that frames it stands above it; filled and outlined float the label inside the box. Use one style per form. A design system may leave some out (the Tanrei system ships stacked only) or add values. — Number input
size	small | medium | large	"medium"	Minimum height of the container: stacked 32 / 40 / 56, as tall as a Button of the same size, so that the box and a Button side by side in one row stand as tall as each other; filled and outlined 40 / 48 / 56, which hold the label that floats inside them. These are the text input's three sizes, small for a bar, a toolbar or a dense row of controls. The hit area always meets the minimum target. A design system may add values. — Number input
value	number	null	The committed number, or null (the platform's absent value) while the field holds none. It changes when the person commits — focus leaves, the action key, a step — not on every keystroke; input carries what is being typed. — Number input
label	string	""	Names the control, visibly and to assistive technology. Required, unless the control names itself (a checkbox or a switch with its own label): then leave it empty and the field adds only help and an error. — Field Names the number input. In a filled or outlined look the input draws it, floating in its box, and the Field draws no label row (FLD-25, NMI-8).
labelHidden	boolean	false	Does not draw the label, which stays the accessible name. For a control whose visible label is elsewhere (a table column, a toolbar). — Field Hides the label wherever it would be drawn: the Field's row, or the input's floating label (FLD-25). Where no message is shown either, the bare number input, named by its own label, is that control without a frame.
placeholder	string	""	A hint shown while the input is empty and the label is not in the input line. Never a replacement for a name. — Number input
supportingText	string	""	Help shown below the control and given to assistive technology as the control's description. While the field is in error it gives way to errorText, unless the design system keeps both (comp.field.error-text.placement append). — Field
errorText	string	""	Shown while error is true, in supportingText's place — or below it, which then stays, where the design system's comp.field.error-text.placement is append: what is wrong and how to put it right, in words. — Field
error	boolean	false	Puts the field in the error condition: the error text is drawn, the control is exposed as invalid and, where it has an error condition of its own, drawn in it. What a value means is the product's to validate; the field never sets this itself. — Field The Field puts its number input in the input's own error condition (FLD-8, NMI-10); the steppers stay as they are.
disabled	boolean	false	Disables the control and draws the frame as disabled. Disable a framed control here, not on the control, so that its label follows. — Field The Field disables its number input, and with it both steppers (FLD-14, NMI-32); the number field is then left out of its form (NUM-48).
readOnly	boolean	false	The number can be focused, selected and copied, but not changed: no key steps it and no stepper is drawn. — Number input
required	boolean	false	What the form asks of the control: true exposes it as required and draws the required mark beside the label. It never validates: a missing answer is the product's to report with error. — Field The Field exposes its number input as required (FLD-10, NMI-12).
optional	boolean	false	Draws the optional tag after the label and adds optionalText to the control's description, because assistive technology has no state for it. Ignored while required is true: a control is never both. — Field
requiredMark	auto | tag | asterisk | none	"auto"	How this control shows that it is required: tag is a small filled Tag with requiredText, asterisk is "*" after the label, none draws nothing and keeps the semantics. Auto takes comp.field.requirement.mark, which follows sys.behavior.requirement-mark, the system's one answer. Ignored unless required is true. — Field
requiredText	string	""	The text of the required tag, in the product's language ("Required", "必須"). The product's: Tanrei has no word for it. Empty reads the product's words; with neither, FLD-24 says what is drawn. — Field
optionalText	string	""	The text of the optional tag, in the product's language ("Optional", "任意"); also read to assistive technology as part of the description. The product's: Tanrei has no word for it. Empty reads the product's words. — Field
min	number	null	The lowest number a commit keeps; a lower one is raised to it. Null for no limit. It is also where the steps are counted from. — Number input
max	number	null	The highest number a commit keeps; a higher one is lowered to it. Null for no limit. — Number input
step	number	1	How far Up Arrow, Down Arrow and a stepper move the number; Page Up and Page Down move ten times as far. It does not limit what may be typed. — Number input
steppers	boolean	true	Draws the two stepper buttons at the end of the field. False for a field in a row too narrow for them, or beside a slider that does their work; the keys still step. — Number input
incrementLabel	string	""	The accessible name of the stepper that steps up, in the product's language ("Increase"). The product's: Tanrei has no word for it. Empty reads the product's words. Required while the steppers are shown. — Number input
decrementLabel	string	""	The accessible name of the stepper that steps down, in the product's language ("Decrease"). The product's: Tanrei has no word for it. Empty reads the product's words. Required while the steppers are shown. — Number input
prefixText	string	""	Fixed text before the number, not part of the value: a currency sign ("$", "¥"). — Number input
suffixText	string	""	Fixed text after the number, not part of the value: the unit ("px", "ms", "%", "kg"). Read to assistive technology with the number. — Number input
valueText	string	""	The value as words ("12 pixels", "3 stars"), given to assistive technology in place of the number with its prefix and suffix. The same text a Slider beside the field takes as its valueText. — Number input
align	start | end	"start"	Where the number stands in the input: at the start, as the text of every other field, or at the end, for a number in a column of numbers whose digits should line up. — Number input
minFractionDigits	number	0	The fewest digits shown after the decimal separator; zeros fill them (2 for an amount of money: "12.00"). — Number input
maxFractionDigits	number	3	The most digits kept after the decimal separator: a commit rounds to it. 0 makes the field hold whole numbers and asks for a keyboard without a separator. — Number input
locale	string	""	A BCP 47 language tag ("en-US", "de-DE", "ar-EG") for how the number is shown and read: its digits and its decimal separator. Empty uses the platform's current locale. The value itself is a number in every locale. — Number input
invalidText	string	""	The words for an input committed with a text that is not a number ("Enter a number"): given to the Field that frames it, which shows them as its error text and, while they are empty, shows its own errorText (NMI-21, FLD-28). — Number input Shown by the Field, in its supporting row (FLD-28).

Slots

Slot	Description
label-icon	A glyph before the label. — Field

Events

Event	Description
input	The person changed the text, or a step changed the value; carries the number the text reads as — not clamped, not rounded — or the empty value while it reads as none. Emitted for every change, not when the product sets value. What a Slider beside the field follows. — Number input
change	A commit changed the value: focus left the field, the action key was pressed, a key or a stepper stepped it, or a held stepper was released; carries the value. — Number input
action	The person pressed the keyboard's action key (Enter, Return, Done). — Number input
entryError	The person committed a text that is not a number; carries the reason (invalid) and invalidText, the words the input has for it. The entry error itself is shown by the Field that frames the input (NMI-21). — Number input

States

Behavior

Requirements in EARS form. Every platform implementation is tested against these ids.

ID	Requirement
NUM-47	THE number field SHALL be a Field that frames one number input, and nothing else. It SHALL give label, labelHidden, supportingText, errorText, error, disabled, required, optional, requiredMark, requiredText and optionalText to its Field and every other prop to its number input, each unchanged; SHALL hold the label-icon slot for its Field; and SHALL emit its number input's events as its own, each once. THE number field SHALL be as wide as the place it stands in, and its number input SHALL fill it: it is a block with no width of its own, as its Field is (FLD-1), around a control that fills the width it is given (NMI-36). It SHALL draw no part of its own, hold no state of its own and have no token of its own: what it shows, how it behaves and what it exposes to assistive technology SHALL be exactly what that Field and that number input do when a product places the one in the other (FLD-1 to FLD-28; NMI-1 to NMI-46) — the label row and its requirement mark (FLD-2 to FLD-6), or the label that floats in the box with the Field's row left out (FLD-25, NMI-7, NMI-8); the supporting row and the error (FLD-7 to FLD-9, FLD-26); the name, the description and the states (FLD-10, FLD-11, FLD-14, NMI-12, NMI-32); a text that is not a number shown as an error in the Field's row, in the input's words (FLD-28, NMI-21); and the two steppers, which are the number input's Buttons and stand inside its box (NMI-25).
NUM-48	WHERE the platform has forms (the web) THE number field SHALL be the one control the form sees: it SHALL take name, submit its number input's value as that input submits it — a decimal number with ASCII digits and a period, or an empty string WHILE it holds none (NMI-35) — reset to the value it was first given, restore it on navigation, report to the form's constraint validation exactly what its number input would report there (a missing value WHILE required is true and it holds none, NMI-12; a bad input WHILE an entry error lasts, NMI-21), and be left out WHILE disabled is true or a disabled group of the form holds it; its number input and its Field SHALL take no part in the form themselves. WHEN the action key asks for the form's submission (NMI-20) the form asked SHALL be the number field's own.
NUM-49	WHEN the number field is given focus — by the product, by a press on any part of it that FLD-12 or NMI-14 gives to the input, or by a form that reports its validity — THE number field SHALL pass the focus to its number input and SHALL add no stop to the focus order: it has one stop, its input, and the steppers are none (NMI-25). A press on a stepper SHALL step and move no focus, in the number field as in the bare input (NMI-26). WHILE focus is inside it THE number field SHALL count as focused for its Field (FLD-13).
NUM-50	IF the number field is placed in a Field THE number field SHALL in debug builds report that it is a field already and that the bare control is the number input, and both SHALL still render (FLD-15). WHILE it stands in a field group THE number field SHALL follow that group's disabled, through its own Field, and take nothing else from the group (FGR-14).
NUM-51	THE number field SHALL have no words of its own and SHALL read none: requiredText and optionalText are read by its Field (FLD-24), incrementLabel and decrementLabel by its number input (NMI-44), each from the instance's prop and then from the product's words.
NUM-52	WHERE the platform has ARIA attributes (the web), WHEN the product sets an aria- attribute on the host, by the attribute or by the ARIA property that reflects it, THE number field SHALL move it to the data-aria- attribute of the same name, so that the host is no second node with its name, description or state, and SHALL expose it on the element that carries its role — an id reference by the elements it names in the host's tree or a tree around it, an error message as part of the description while the number field is invalid — except those the number field owns (aria-label, aria-labelledby, aria-disabled), which it SHALL move and not expose: its name is label (NUM-47). WHEN the product removes the aria- attribute or its data-aria- twin, or sets the ARIA property that reflects it (ariaLabel, ariaDescribedByElements…) to null, THE number field SHALL take it off that element. WHEN the product sets an aria- attribute the number field owns THE number field SHALL report it in debug builds.

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-field	TanreiNumberField	TanreiNumberField	TanreiNumberField	NumberField
variant · Property	variant	variant	variant	variant	variant
size · Property	size	size	size	size	size
value · Property	value	value	value	value	value
label · Property	label	label	label	labelText	label
labelHidden · Property	labelHidden	labelsHidden	labelHidden	labelHidden	labelHidden
placeholder · Property	placeholder	prompt	placeholder	hintText	placeholder
supportingText · Property	supportingText	supportingText	supportingText	helperText	supportingText
errorText · Property	errorText	errorText	errorText	errorText	errorText
error · Property	error	error	isError	isError	error
disabled · Property	disabled	disabled	enabled	enabled	disabled
readOnly · Property	readOnly	readOnly	readOnly	readOnly	readOnly
required · Property	required	isRequired	required	required	required
optional · Property	optional	isOptional	optional	optional	optional
requiredMark · Property	requiredMark	requiredMark	requiredMark	requiredMark	requiredMark
requiredText · Property	requiredText	requiredText	requiredText	requiredText	requiredText
optionalText · Property	optionalText	optionalText	optionalText	optionalText	optionalText
min · Property	min	in	min	min	min
max · Property	max	in	max	max	max
step · Property	step	step	step	step	step
steppers · Property	noSteppers	steppers	steppers	steppers	steppers
incrementLabel · Property	incrementLabel	incrementLabel	incrementContentDescription	incrementSemanticLabel	incrementAccessibilityLabel
decrementLabel · Property	decrementLabel	decrementLabel	decrementContentDescription	decrementSemanticLabel	decrementAccessibilityLabel
prefixText · Property	prefixText	prefix	prefix	prefixText	prefix
suffixText · Property	suffixText	suffix	suffix	suffixText	suffix
valueText · Property	valueText	valueText	stateDescription	semanticValue	valueText
align · Property	align	align	align	align	align
minFractionDigits · Property	minFractionDigits	minFractionDigits	minFractionDigits	minFractionDigits	minFractionDigits
maxFractionDigits · Property	maxFractionDigits	maxFractionDigits	maxFractionDigits	maxFractionDigits	maxFractionDigits
locale · Property	locale	locale	locale	locale	locale
invalidText · Property	invalidText	invalidText	invalidText	invalidText	invalidText
input · Event	input	onInput	onInput	onInput	onInput
change · Event	change	value	onValueChange	onChanged	onValueChange
action · Event	action	onSubmit	keyboardActions	onSubmitted	onSubmitEditing
entryError · Event	entryerror	onEntryError	onEntryError	onEntryError	onEntryError
Notes	The tag is tanrei-number-field, the class TanreiNumberField, the React name NumberField. Members: <tanrei-field> holding one <tanrei-number-input> in its default slot; the product places none. The host is display: block, as the Field is, so a number field is as wide as its place and its input fills it (NUM-47, NMI-36). Value member: tanrei-number-input. The host is the form's element — name, the value and its state as the input gives them (the decimal string, or nothing while disabled), validity anchored on the input (valueMissing, badInput), reset to the value attribute, restore, form, a disabled fieldset — and the input inside has no name. The value property is number | null and the attribute a decimal string, declared as the member declares them. Props, set as properties on the member each is from. On the Field: label, labelHidden, supportingText, errorText, error, disabled, required, optional, requiredMark, requiredText, optionalText. On the number input: variant, size, value, placeholder, readOnly, min, max, step, noSteppers (the inverse of steppers, attribute no-steppers), incrementLabel, decrementLabel, prefixText, suffixText, valueText, align, minFractionDigits, maxFractionDigits, locale, invalidText. Attributes are the members' own: kebab-case, except readonly, min, max and step. Props of one name on both members — label, labelHidden, error, disabled — are the Field's; the input's are never set by the element and reach the input through the connection. Events: input, change, action and entryerror are the number input's own composed events and leave by themselves, with the host as their target and value already new at change; action stays cancelable. None is stopped and none is copied; a stepper's own click is the Button's and is not an event of the spec. Slots: label-icon is passed to the Field by a slot element of the same name, rendered only while the host has a child for it. The element has no other slot: the steppers are the input's own Buttons, not the product's children. Parts: the member hosts are field and number-input. Exported from the Field: label, label-icon, requirement-label, supporting-text. Exported from the number input: container, outline, active-indicator, label, requirement-label, input, prefix, suffix, stepper. Two names collide, label and requirement-label. Each is exported with its member's name before it, always (field-label, number-input-label, field-requirement-label, number-input-requirement-label), and under the bare name from both members as well, because the two are one thing to a person and are never drawn at once: FLD-25 is the sentence that holds it. stepper is a part of a member's small part: the number input exports the two Buttons' hosts under that name, and nothing of the Button's inside is exported. Focus: the shadow root does not delegate. focus() and blur() call the number input's; a press on the label row focuses the input by FLD-12, a press on the box by NMI-14, a press on a stepper steps and moves no focus (NMI-26), and a press on the help does nothing. The connection is the Field's with its control (FLD-25, FLD-26, FLD-28; NMI-45); the element takes no part in it. Parts and tokens of its own: none. The element writes no custom property: --tanrei-comp-field-*, --tanrei-comp-input-box-*, --tanrei-comp-number-input-* and, for the steppers, --tanrei-comp-button-* reach the members by inheritance, and one number field is set apart by setting any of them on the element. What its twin cannot do that it does: nothing. The twin: <tanrei-field label="Quantity" supporting-text="Up to 99 per order." required><tanrei-number-input name="quantity" min="1" max="99" increment-label="Increase" decrement-label="Decrease"></tanrei-number-input></tanrei-field>. Words: none of its own (NUM-51).	Not built on this platform yet: the number input as a view of its own, and this as the Field around it. Its name, its props and its idiom: TanreiNumberField("Quantity", value: $quantity, in: 1...99, step: 1), shaped as the platform's own pair, TextField(_:value:format:) and Stepper(value:in:step:): value is a Binding<Double?> (and an overload for Binding<Int?>, which sets maxFractionDigits to 0), written on every commit, which is the change event; min and max are one optional ClosedRange or partial range. Built on TextField with .keyboardType(.decimalPad) (.numbersAndPunctuation where a minus sign is needed) and a FormatStyle from locale. labelHidden follows .labelsHidden(), disabled follows .disabled(_:), action is onSubmit:. The field carries .accessibilityAdjustableAction for increment and decrement and .accessibilityValue with the value text; the steppers are TanreiButtons with .focusable(false). The drawing is Tanrei's on every Apple platform; Stepper itself is not used to draw. The product's words are read from the \.tanreiWords environment value.	Not built on this platform yet: the number input as a view of its own, and this as the Field around it. Its name, its props and its idiom: Compose idiom, as TextField: TanreiNumberField(value: Double?, onValueChange: (Double?) -> Unit, label = "Quantity", min = 1.0, max = 99.0); the caller keeps value (state hoisting) and onValueChange is called on a commit, onInput while typing. enabled is the inverse flag and isError, readOnly, prefix and suffix keep Compose's names. Built on BasicTextField with KeyboardOptions(keyboardType = KeyboardType.Decimal) (Number while maxFractionDigits is 0) and java.text.DecimalFormat for locale. Semantics: Role has no spin button, so the field sets stateDescription (the value text), ProgressBarRangeInfo for the limits and setProgress, plus custom accessibility actions for increase and decrease; the steppers are TanreiButtons with Modifier.focusProperties { canFocus = false }. A held stepper repeats from pointerInput with the component's own timings. The product's words are read from LocalTanreiWords.	Not built on this platform yet: the number input as a view of its own, and this as the Field around it. Its name, its props and its idiom: Flutter idiom, as TextField and InputDecoration: TanreiNumberField(value: 12, onChanged: (num? v) {…}, labelText: 'Quantity', min: 1, max: 99), with hintText, helperText, errorText, prefixText, suffixText and enabled keeping InputDecoration's names, enabled the inverse flag. TanreiNumberFormField wraps it as a FormField<num?> (validator, onSaved, autovalidateMode). Built on TextField with TextInputType.numberWithOptions(decimal:, signed:) and no input formatter that refuses characters (NMI-16); formatting and parsing use NumberFormat from the intl package with locale. Semantics(value:, increasedValue:, decreasedValue:, onIncrease:, onDecrease:) makes it adjustable; the steppers are TanreiButtons with canRequestFocus: false. Tabular figures are FontFeature.tabularFigures(). The product's words are read from the TanreiWords inherited widget, which the app fills from its own localizations.	Not built on this platform yet: the number input as a view of its own, and this as the Field around it. Its name, its props and its idiom: React Native idiom, as TextInput: <NumberField label="Quantity" value={quantity} onValueChange={setQuantity} min={1} max={99} /> with value: number | null. Built on TextInput with inputMode="decimal" ("numeric" while maxFractionDigits is 0; keyboardType="numbers-and-punctuation" on iOS where a minus sign is needed, because its decimal pad has none). accessibilityRole="adjustable", accessibilityValue={{ min, max, now, text }} and accessibilityActions increment and decrement with onAccessibilityAction; the steppers are Buttons with focusable={false}. Formatting uses Intl.NumberFormat where the engine has it (Hermes does) and falls back to ASCII digits with the locale's separator. fontVariant: ['tabular-nums']. Follows the app's direction where an ancestor's is not known. The product's words are read from the TanreiWordsProvider context.

Tokens

Token	Aliases	Resolved (light)
--tanrei-comp-field-counter-gap	sys.space.space200	16px
--tanrei-comp-field-error-text-gap	sys.space.space50	4px
--tanrei-comp-field-error-text-placement	—	0
--tanrei-comp-field-label-icon-gap	sys.space.space100	8px
--tanrei-comp-field-label-icon-size	sys.icon.small	20px
--tanrei-comp-field-label-gap	sys.space.space100	8px
--tanrei-comp-field-motion-state-duration	sys.motion.role.state.default	250ms
--tanrei-comp-field-motion-state-easing	sys.motion.easing.state	cubic-bezier(0.2, 0, 0, 1)
--tanrei-comp-field-requirement-asterisk-gap	sys.space.space25	2px
--tanrei-comp-field-requirement-gap	sys.space.space100	8px
--tanrei-comp-field-requirement-mark	sys.behavior.requirement-mark	0
--tanrei-comp-field-standard-counter-color	sys.color.on-surface-variant	#4b4b4b
--tanrei-comp-field-standard-disabled-counter-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-disabled-error-text-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-disabled-error-counter-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-disabled-error-label-icon-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-disabled-error-label-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-disabled-error-required-asterisk-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-disabled-error-supporting-text-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-disabled-error-value-text-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-disabled-label-icon-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-disabled-label-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-disabled-required-asterisk-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-disabled-supporting-text-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-disabled-value-text-color	—	#1b1b1b · 38%
--tanrei-comp-field-standard-error-text-color	sys.color.error	#cd262f
--tanrei-comp-field-standard-error-counter-color	sys.color.on-surface-variant	#4b4b4b
--tanrei-comp-field-standard-error-label-icon-color	sys.color.on-surface-variant	#4b4b4b
--tanrei-comp-field-standard-error-label-color	sys.color.on-surface	#1b1b1b
--tanrei-comp-field-standard-error-required-asterisk-color	sys.color.primary	#1b1b1b
--tanrei-comp-field-standard-error-supporting-text-color	sys.color.on-surface-variant	#4b4b4b
--tanrei-comp-field-standard-error-value-text-color	sys.color.on-surface-variant	#4b4b4b
--tanrei-comp-field-standard-focused-counter-color	—	#4b4b4b
--tanrei-comp-field-standard-focused-error-text-color	—	#cd262f
--tanrei-comp-field-standard-focused-error-counter-color	—	#4b4b4b
--tanrei-comp-field-standard-focused-error-label-icon-color	—	#4b4b4b
--tanrei-comp-field-standard-focused-error-label-color	—	#1b1b1b
--tanrei-comp-field-standard-focused-error-required-asterisk-color	—	#1b1b1b
--tanrei-comp-field-standard-focused-error-supporting-text-color	—	#4b4b4b
--tanrei-comp-field-standard-focused-error-value-text-color	—	#4b4b4b
--tanrei-comp-field-standard-focused-label-icon-color	—	#4b4b4b
--tanrei-comp-field-standard-focused-label-color	—	#1b1b1b
--tanrei-comp-field-standard-focused-required-asterisk-color	—	#1b1b1b
--tanrei-comp-field-standard-focused-supporting-text-color	—	#4b4b4b
--tanrei-comp-field-standard-focused-value-text-color	—	#4b4b4b
--tanrei-comp-field-standard-label-icon-color	sys.color.on-surface-variant	#4b4b4b
--tanrei-comp-field-standard-label-color	sys.color.on-surface	#1b1b1b
--tanrei-comp-field-standard-required-asterisk-color	sys.color.primary	#1b1b1b
--tanrei-comp-field-standard-supporting-text-color	sys.color.on-surface-variant	#4b4b4b
--tanrei-comp-field-standard-value-text-color	sys.color.on-surface-variant	#4b4b4b
--tanrei-comp-field-supporting-text-gap	sys.space.space50	4px
--tanrei-comp-field-value-text-gap	sys.space.space200	16px
--tanrei-comp-field-label-typescale	sys.typescale.label	500 14px/1.4286
--tanrei-comp-field-supporting-text-typescale	sys.typescale.label-small	500 12px/1.3333
--tanrei-comp-field-value-text-typescale	sys.typescale.label	500 14px/1.4286

Fixtures

Canonical renderings. Every platform snapshots each fixture under the same id so the results can be compared.

variant: stacked (38)

stacked-empty

variant: stacked label: Quantity incrementLabel: Increase decrementLabel: Decrease

stacked-value

variant: stacked value: 12 label: Quantity incrementLabel: Increase decrementLabel: Decrease

stacked-placeholder

variant: stacked label: Quantity placeholder: 1 to 99 incrementLabel: Increase decrementLabel: Decrease

stacked-large

variant: stacked size: large value: 12 label: Quantity incrementLabel: Increase decrementLabel: Decrease

stacked-label-hidden

variant: stacked value: 12 label: Quantity labelHidden: true incrementLabel: Increase decrementLabel: Decrease

stacked-supporting

variant: stacked value: 12 label: Quantity supportingText: Up to 99 per order. incrementLabel: Increase decrementLabel: Decrease

stacked-error

variant: stacked value: 0 label: Quantity supportingText: Up to 99 per order. errorText: Order at least 1. error: true incrementLabel: Increase decrementLabel: Decrease

stacked-disabled

variant: stacked value: 12 label: Quantity disabled: true incrementLabel: Increase decrementLabel: Decrease

stacked-read-only

variant: stacked value: 12 label: Quantity readOnly: true

stacked-at-min

variant: stacked value: 1 label: Quantity min: 1 max: 99 incrementLabel: Increase decrementLabel: Decrease

stacked-at-max

variant: stacked value: 99 label: Quantity min: 1 max: 99 incrementLabel: Increase decrementLabel: Decrease

stacked-no-steppers

variant: stacked value: 12 label: Quantity steppers: false

stacked-unit

variant: stacked value: 8 label: Corner radius min: 0 step: 0.25 incrementLabel: Increase decrementLabel: Decrease suffixText: px

stacked-percent

variant: stacked value: 40 label: Opacity min: 0 max: 100 incrementLabel: Increase decrementLabel: Decrease suffixText: %

stacked-prefix

variant: stacked value: 120 label: Amount incrementLabel: Increase decrementLabel: Decrease prefixText: $ suffixText: USD minFractionDigits: 2 maxFractionDigits: 2

stacked-negative-decimal

variant: stacked value: -0.25 label: Letter spacing step: 0.01 incrementLabel: Increase decrementLabel: Decrease suffixText: px

stacked-align-end

variant: stacked value: 40 label: Tone min: 0 max: 100 incrementLabel: Increase decrementLabel: Decrease align: end

stacked-long-number

variant: stacked value: 8336817000 label: Population steppers: false

stacked-label-icon

variant: stacked value: 200 label: Duration incrementLabel: Increase decrementLabel: Decrease suffixText: ms slots: label-icon

stacked-required

variant: stacked label: Quantity required: true requiredText: Required incrementLabel: Increase decrementLabel: Decrease

stacked-optional

variant: stacked label: Quantity optional: true optionalText: Optional incrementLabel: Increase decrementLabel: Decrease

stacked-required-asterisk

variant: stacked label: Quantity required: true requiredMark: asterisk incrementLabel: Increase decrementLabel: Decrease

stacked-required-error

variant: stacked label: Quantity errorText: Enter how many you need. error: true required: true requiredText: Required incrementLabel: Increase decrementLabel: Decrease

stacked-required-disabled

variant: stacked value: 12 label: Quantity disabled: true required: true requiredText: Required incrementLabel: Increase decrementLabel: Decrease

stacked-required-label-icon

variant: stacked value: 200 label: Duration required: true requiredText: Required incrementLabel: Increase decrementLabel: Decrease suffixText: ms slots: label-icon

stacked-required-ja

variant: stacked value: 12 label: 数量 required: true requiredText: 必須 incrementLabel: 増やす decrementLabel: 減らす suffixText: 個

stacked-optional-ja

variant: stacked label: 数量 supportingText: 1 回の注文で 99 個まで。 optional: true optionalText: 任意 incrementLabel: 増やす decrementLabel: 減らす

stacked-locale-de

variant: stacked value: 1.5 label: Gewicht step: 0.1 incrementLabel: Erhöhen decrementLabel: Verringern suffixText: kg locale: de-DE

stacked-locale-ar

variant: stacked value: 12 label: الكمية incrementLabel: زيادة decrementLabel: إنقاص locale: ar-EG direction: rtl

stacked-required-rtl

variant: stacked value: 12 label: الكمية supportingText: حتى 99 لكل طلب. required: true requiredText: مطلوب incrementLabel: زيادة decrementLabel: إنقاص direction: rtl slots: label-icon

stacked-unit-rtl

variant: stacked value: -12.5 label: רוחב incrementLabel: הגדלה decrementLabel: הקטנה suffixText: px direction: rtl

stacked-error-rtl

variant: stacked value: 0 label: כמות errorText: יש להזמין לפחות 1. error: true optional: true optionalText: רשות incrementLabel: הגדלה decrementLabel: הקטנה direction: rtl

long-label

variant: stacked value: 2 label: How many copies of the printed annual re… supportingText: Each copy is 180 pages; orders of more t… required: true requiredText: Required incrementLabel: Increase decrementLabel: Decrease

beside-slider

variant: stacked value: 1.5 label: Scale labelHidden: true min: 0.25 max: 4 step: 0.05 steppers: false suffixText: × valueText: 1.5 times align: end

stacked-unit-own-script-rtl

variant: stacked value: 12 label: الوزن min: 0 step: 0.5 incrementLabel: زيادة decrementLabel: إنقاص suffixText: كغم direction: rtl

stacked-prefix-rtl

variant: stacked value: 120 label: المبلغ incrementLabel: زيادة decrementLabel: إنقاص prefixText: $ suffixText: USD minFractionDigits: 2 maxFractionDigits: 2 direction: rtl

stacked-percent-rtl

variant: stacked value: 40 label: العتامة min: 0 max: 100 incrementLabel: زيادة decrementLabel: إنقاص suffixText: % direction: rtl

stacked-align-end-unit-rtl

variant: stacked value: 44 label: גודל steppers: false suffixText: px align: end direction: rtl

variant: filled (6)

filled-empty

variant: filled label: Quantity incrementLabel: Increase decrementLabel: Decrease

filled-value

variant: filled value: 12 label: Quantity incrementLabel: Increase decrementLabel: Decrease

filled-large

variant: filled size: large value: 12 label: Quantity incrementLabel: Increase decrementLabel: Decrease

filled-error

variant: filled value: 0 label: Quantity errorText: Order at least 1. error: true incrementLabel: Increase decrementLabel: Decrease

filled-disabled

variant: filled value: 12 label: Quantity disabled: true incrementLabel: Increase decrementLabel: Decrease

filled-unit

variant: filled value: 8 label: Corner radius incrementLabel: Increase decrementLabel: Decrease suffixText: px

variant: outlined (6)

outlined-empty

variant: outlined label: Quantity incrementLabel: Increase decrementLabel: Decrease

outlined-value

variant: outlined value: 12 label: Quantity incrementLabel: Increase decrementLabel: Decrease

outlined-large

variant: outlined size: large value: 12 label: Quantity incrementLabel: Increase decrementLabel: Decrease

outlined-error

variant: outlined value: 0 label: Quantity errorText: Order at least 1. error: true incrementLabel: Increase decrementLabel: Decrease

outlined-disabled

variant: outlined value: 12 label: Quantity disabled: true incrementLabel: Increase decrementLabel: Decrease

outlined-required

variant: outlined label: Quantity required: true requiredText: Required incrementLabel: Increase decrementLabel: Decrease

Generated from specs/number-field.spec.json, tokens/comp/field.tokens.json, design/tokens/

What the web draws differently

link

• The element’s shadow root holds a <tanrei-field> with a <tanrei-number-input> in it. Importing the number field defines both.
• The number field is a form-associated element, and the one control its form meets. It takes name and submits its value as a plain decimal number (12.5) whatever the locale shows. It resets to the value attribute, and reports a missing value while required and it holds none, and a bad input while its text is not a number.
• It is a block as wide as its place. In a place that gives no width, a long label makes it wider than its box: give it a width there.
• Parts are the members’, under their own names: label, label-icon, requirement-label and supporting-text from the field; container, outline, active-indicator, input, prefix, suffix and stepper from the number input. label and requirement-label reach whichever of the two is drawn; field-label and number-input-label reach one. The two members are the parts field and number-input.
• entryerror’s detail.text is the input’s invalidText, empty where none was given. The detail types are the number input’s: TanreiNumberInputInputDetail and TanreiNumberInputEntryErrorDetail.
• steppers is the inverse attribute no-steppers, and readOnly is readonly.
• input is a CustomEvent with detail.value. change and action are plain events: read value from the element. Unless action is cancelled, the form is then asked to submit.
• Without locale the field reads the nearest lang attribute, then the browser’s language.
• Besides the locale’s separator, a period is read as the decimal separator wherever the locale does not group with periods.
• A page key steps ten steps on the step’s own grid, as a slider’s does: with a step of 2, Page Up from 42 gives 62, then 82.
• On iOS and iPadOS the field asks for the full keyboard while a negative number may be typed, because the decimal keypad there has no minus sign.
• Before the element is defined it has no size. Reserve the height.

Guidelines

link

Number field, text field or slider

link

Aspect	Number field	Text field	Slider
Holds	A number	Any text	A number within a range
Chosen by	Typing or stepping	Typing	Dragging
Good for	A value that is known	Digits that are not a quantity	A value chosen by feel

A postal code, a card number, a telephone number and a one-time code are digits, but not quantities: nobody adds one to a postal code. Use a text field for them.

Do

link

• Write a label that names what is counted, and keep it visible in a form.
• Put the unit in suffixText, and a currency sign in prefixText.
• Give valueText where the suffix would be read badly: “1.5 times” for ×.
• Write invalidText so that it says what to type: “Enter a number.”
• Set maxFractionDigits to 0 for whole numbers. The keyboard then has no separator.
• Give incrementLabel and decrementLabel, on the field or once for the whole product with setWords(). Tanrei ships no words: a stepper without a name is still drawn and still steps for a pointer, and is kept from assistive technology, where the spin button steps by itself.

Don’t

link

• Don’t use a number field for digits that are not a quantity.
• Don’t save on input. It fires at every keystroke; change carries the committed value.
• Don’t expect min and max to correct a value you set yourself. They apply to what the person commits.
• Don’t put a control for choosing the unit inside the field. Put a select beside it.
• Don’t put a number field inside a field. It is a field already; the control a field frames is the number input.
• Don’t hide the label of a number field to place the box under a label of your own. Use the number input.

Accessibility

link

Role

spinbutton

Labeling

The number field adds nothing to what its members expose and coordinates nothing: the Field gives the number input its name, its description and its required, invalid and disabled states (FLD-8, FLD-10, FLD-11, FLD-14), and the number input carries them on its own element with its value, its limits and its value text (NMI-12, NMI-34). Assistive technology meets one spin button named by label and two buttons that are no focus stops, exactly as it meets a Field around a number input written by hand.

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
Every key	The number input's (its accessibility block; NMI-20, NMI-23). The number field handles no key and adds no focus stop (NUM-49).

Notes

• One level down is the same thing: a Field with a number input in it. Every fixture has that pair as its twin, and the accessibility tree of the two is the same (NUM-47).
• On the web the two members stand in the number field's own shadow root, so the form meets the number field and not the input (NUM-48); focus passes through to the input (NUM-49).
• Two levels down, for a number whose label is elsewhere and that shows no message, is the number input alone, named by its own label: beside a slider under one row title, in a table, in a toolbar.

Generated from specs/number-field.spec.json, tokens/sys/measure.tokens.json

What the component handles

link

• The input is a spin button. Its name is label, drawn or hidden, and never the placeholder.
• Its value is the committed number, and its limits are min and max.
• The shown supporting or error text is its description, with optionalText while the field is optional.
• It is exposed as invalid while error is true or its text is not a number, as required while required is set, and as read-only.
• An error that appears while the field has focus is announced once, politely — a text that is not a number too.
• The steppers are buttons named by decrementLabel and incrementLabel; one that nobody named is hidden from assistive technology. They are outside the focus order, because the arrow keys step from the input; a person exploring by touch still finds them.
• A press on a stepper does not move focus, so it does not raise the on-screen keyboard.
• While an input method is composing, the field reads nothing and handles no key.
• The wheel never changes the number.
• The field’s hit area meets the minimum target, and each stepper is a full target.
• At 200% text the label and the help wrap. The number stays on one line, and scrolls.
• Where the row cannot hold the number and the steppers side by side — at 200% text in a narrow window, with a prefix and a long suffix — the steppers move to a row of their own below the number, at the box’s end. They are never hidden, because on touch they are the only way to step.
• In forced colors the field gains an edge, and an error is told by its words and the invalid state.
• In a right-to-left layout the steppers and the label are mirrored: the steppers stand at the left end. The number and its unit are written as the unit’s own script writes them: a unit in Latin letters or signs after the number, from left to right, and a unit in the page’s script at the number’s left. What is read aloud does not change.

Known gaps on the web:

• Chromium reads the number without its unit: it takes the value text from the text in the input, and passes over the one the field names. Name the unit in the label where it matters.
• Before the element is defined, nothing is drawn.

What you need to do

link

• Give every number field a label.
• Write invalidText on the field. Give requiredText, optionalText, incrementLabel and decrementLabel on the field, or once for the whole product with setWords(). Tanrei ships no words; a missing one is reported in development. See The product’s words.
• Validate the value yourself, set error, and write errorText so that it says how to put the number right.
• Give both a slider and the number input beside it the same name.