Select field

Overview

link

Web

tanrei-select-field

schedule

SwiftUI

TanreiSelectField

radio_button_unchecked

Jetpack Compose

TanreiSelectField

radio_button_unchecked

Flutter

TanreiSelectField

radio_button_unchecked

React Native

SelectField

radio_button_unchecked

Variants not shipped in

tanrei: filled, outlined

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

A required select field, and one grouped with a glyph that stands for the field

CanadaFranceJapanKenyaNew ZealandpublicTokyoSeoulLisbonBerlin

Use a select field in a form for one value out of a list that is known and closed: a country, a time zone, a plan. It is the ordinary case, ready to use: a label, the box that shows the chosen option and opens the list, a line of help, and the words for a value that was refused.

Built from a field and a select. The field is the frame: the label, the required or optional mark, the help and the error. The select is the control: the trigger, the list and everything a person does in them. The select 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, and the options you give it are its select’s.

It is as wide as the place it is put in, and its box fills it. Give it a narrower place for a narrower box.

On the web it is <tanrei-select-field> with <tanrei-option> children. The other platforms have not implemented it yet.

Usage

link

The options are children of the select field: each has a value and a label. value names the chosen one. change and toggle are the select’s own events, and when either is heard the field’s value and open are already the new ones.

<form>
  <tanrei-select-field name="country" label="Country" value="jp" required required-text="Required"
    supporting-text="Where your invoices are addressed.">
    <tanrei-option value="ca">Canada</tanrei-option>
    <tanrei-option value="jp">Japan</tanrei-option>
  </tanrei-select-field>
</form>

<!-- Grouped, with a line under a label and a glyph that stands for the field. -->
<tanrei-select-field label="Time zone" value="Europe/Lisbon">
  <span slot="leading-icon">public</span>
  <tanrei-option-group label="Asia">
    <tanrei-option value="Asia/Tokyo" supporting-text="UTC+9">Tokyo</tanrei-option>
  </tanrei-option-group>
  <tanrei-option-group label="Europe">
    <tanrei-option value="Europe/Lisbon" supporting-text="UTC+0">Lisbon</tanrei-option>
  </tanrei-option-group>
</tanrei-select-field>

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

  const country = document.querySelector('[name="country"]');
  // The person chose another option. The value is already the new one.
  country.addEventListener('change', () => save(country.value));
  // Opened or closed by the person; a close says why.
  country.addEventListener('toggle', (e) => console.log(e.detail.open, e.detail.reason));
  // Validation is yours: the select field never sets error itself.
  country.error = submitted && !ships(country.value);
  country.errorText = 'We cannot ship there yet. Choose another country.';
</script>

import { Option, SelectField } from '@tanrei/react';

<SelectField label="Country" value={country} required requiredText="Required" onChange={(event) => setCountry(event.currentTarget.value)}>
  <Option value="ca">Canada</Option>
  <Option value="jp">Japan</Option>
</SelectField>

One level down

link

The same field, written by hand from its two members, is the same picture and the same control to assistive technology:

<tanrei-field label="Country" required required-text="Required"
  supporting-text="Where your invoices are addressed.">
  <tanrei-select name="country" placeholder="Choose a country">
    <tanrei-option value="jp">Japan</tanrei-option>
    <tanrei-option value="ke">Kenya</tanrei-option>
  </tanrei-select>
</tanrei-field>

The same field written by hand: a field with a select in it

JapanKenya

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

You need	Use
A label, the box, help and an error	The select field
Something of your own inside the frame, beside or below the box	A field with a select and your own element in it
The box alone, where its label stands elsewhere: a theme in a bar, a sort order in a toolbar, a cell of a table	The select alone, named by its own label
A list long enough that people would rather type than scroll	A combobox

What changes one level down is where things are said. name, value and the options are on the select, which is then the control the form meets, and its events are heard on it. label, error and disabled stay on the field, which passes them to the control: do not set the select’s own.

Specs

link

Supporting text with a disabled option, optional, an error, read-only and disabled

FreeTeamEnterpriseEurope, the Middle East and AfricaAsia and the PacificJapanKenyaJapanKenyaJapanKenya

Filled and outlined: the field's label floats in the select's box, with an asterisk for a required field

JapanKenyaJapanKenya

Under m3-like

What each member gives

link

Aspect	From the field	From the select
Properties	label, labelHidden, supportingText, errorText, error, disabled, required, optional, requiredMark, requiredText, optionalText	variant, size, value, placeholder, readOnly, open, separation, iconSpace, status, statusText, emptyText
Events	—	change, toggle
Slots	label-icon	leading-icon, and the options
Tokens	comp.field.*	comp.input-box.* for the box, which every input box reads; comp.select.* for the list

The select has a label, a labelHidden, an error and a disabled of its own. They are not properties of the select field: the field’s label names the control, its error puts the box in its error condition and its disabled disables it. So you set each of them once, on the select field, and its label changes with the control.

In the stacked look the label is the field’s row above the box. In the filled and the outlined look the select draws the same label itself, floating in its box, and the field draws no label row; a required field is then marked by an asterisk after the label, whichever mark the design system names. The help starts where the value starts, past a leading icon. While the list is open the label and the help are drawn focused, as the box is.

What the trigger and the list do — opening, the arrow keys, typing, choosing, the groups — is on the select’s page. What the frame does — the required mark, the help, the error and how it is announced — is on the field’s page.

Setting one field apart

link

The select field has no token of its own. Its frame reads the field’s tokens and its box and its list the select’s, wherever they are set. To change one instance, set the member’s token on it:

<tanrei-select-field label="Country"
  style="--tanrei-comp-field-label-gap: 12px"></tanrei-select-field>

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 select floats the label it draws no label row.
2 select	The select, as the Field's one control: the trigger with the value it shows, its leading icon and its chevron, the label that floats in it in the looks that float one, and the list of options that opens from it.

Properties

Property	Type	Default	Description
variant	stacked | filled | outlined	"stacked"	The text input's three looks, so that a select 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. — Select
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. The text input's three sizes: medium and large for forms, small for a select in an app bar, a toolbar or a dense row of controls, where nothing frames it. The hit area always meets the minimum target. A design system may add values. — Select
value	string	""	The value of the chosen option. The select shows that option's label; while value names no option it shows the placeholder. An option whose value is the empty string is a choice like any other ("None", "Any") and is the chosen one while value is empty. — Select
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 select. In a filled or outlined look the select draws it, floating in its box, and the Field draws no label row (FLD-25, SEL-15).
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 select's floating label (FLD-25).
placeholder	string	""	A hint shown while nothing is chosen and the label is not in the line ("Choose a country"). Never a replacement for label, and never a choice. — Select
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 select in the select's own error condition (FLD-8, SEL-9).
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 select (FLD-14, SEL-46); the select field is then left out of its form (SEF-2).
readOnly	boolean	false	The value is shown, can be focused and is submitted, but cannot be changed: the list does not open and no chevron is drawn. — Select
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 select as required (FLD-10, SEL-11).
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
open	boolean	false	Whether the list is shown. The select opens and closes itself and emits toggle; the product may also set it. Ignored while the select is disabled or read-only or has nothing to show: no option, no status row and no empty text (SEL-61). — Select
separation	auto | divider | gap	"auto"	How a group of options is told from what is next to it. divider: a line between them. gap: empty space and no line. Auto takes comp.select.separation, which follows the design system's choice. — Select
iconSpace	auto | always | never	"auto"	Whether an option keeps the room of the leading icon column where it has no icon, so that the labels of a section start on one line — a section being an option group, or a run of adjacent options outside any group. auto: an option keeps the column while another option of its section has a leading icon, so that a section without icons starts its labels where the row's content starts. always: every option keeps it. never: only an option that has an icon has the column. The menu's iconSpace, with the same values and default (SEL-66). — Select
density	regular | compact	"regular"	How much room an option of the list takes: its least height, its paddings, the gap between its columns and the size of its glyphs (the leading icon, the check), and never its text style. regular (a 48 row in the default system) is for a product used by touch as well as by pointer; compact (a 32 row with 20 glyphs, the menu's compact row) is for a tool used with a pointer, whose lists are long. For touch an option is never lower than the touch target in either (SEL-37). The field's own box is not changed: its height is size's. A design system may add values. — Select
status	idle | loading | error	"idle"	What the product's source of options is doing, which the product sets: idle (the options given are final), loading (options are on their way: the status row shows a loading indicator and the list is marked busy) or error (the source failed: the status row shows statusText in the error color, announced at once). The combobox's and the search's values, with the same meaning. The select never loads anything itself. — Select
statusText	string	""	The status row's text, in the product's language, read to assistive technology when the list opens and when it changes: a count ("20 of 340 projects shown"), that loading failed ("Projects could not be loaded"), or, while status is loading, the loading indicator's name ("Loading projects"). Empty draws no status row unless status is loading. — Select
emptyText	string	""	Shown in the list while the select holds no option, status is idle and statusText is empty, in the product's language ("No projects yet"), so that the select still opens and says why there is nothing to choose. The product's: Tanrei has no words for it. Empty reads the product's words (noOptionsText); with neither, the select has nothing to show and does not open (SEL-61), and it is reported. — Select

Slots

Slot	Description
leading-icon	A glyph at the start of the container that stands for the field whatever is chosen (a globe before a language). It takes the place of the chosen option's own glyph. — Select
label-icon	A glyph before the label. — Field

Events

Event	Description
change	The person chose an option whose value differs from the select's; carries the new value. Not emitted when the product sets value, when the chosen option is chosen again, or while the person only moves through the list. — Select
toggle	The list was opened or closed by the person; carries the new open and, for a close, the reason: select, escape, back, outside, focus-out, anchor-hidden, press or tab (in the platform's casing). After a choice it follows change. — Select

Items

The kinds of item the component repeats. A fixture lists its items in order; each platform names each kind in its own idiom.

option

One choice of the select: a label, the value it stands for, and optionally a supporting line and a glyph.

Property	Type	Default	Description
label	string	""	The option's text and its accessible name; the container shows it once the option is chosen. Required.
value	string	""	Identifies the choice: the option is the chosen one while the select's value equals it. Unique within the select. The empty string is a value like any other, for an option that stands for no choice ("None").
supportingText	string	""	A line below the label that says more about the choice. Shown in the list, not in the container.
leadingIcon	string	""	The name of an icon (a glyph of the system's icon set) before the label; the container shows it too while the option is chosen and the select has no leading icon of its own.
disabled	boolean	false	Prevents the option from being chosen. It stays reachable with the arrow keys.

Spec	Web	SwiftUI	Jetpack Compose	Flutter	React Native
Item	tanrei-option	TanreiSelectOption	TanreiSelectOption	TanreiSelectOption	SelectOption
label · Property	label	title	text	label	label
value · Property	value	tag	value	value	value
supportingText · Property	supportingText	supportingText	supportingText	supportingText	supportingText
leadingIcon · Property	leadingIcon	leadingIcon	leadingIcon	leadingIcon	leadingIcon
disabled · Property	disabled	disabled	enabled	enabled	disabled
Notes	<tanrei-option> children of <tanrei-select-field>, exactly as of <tanrei-select>: the product's elements in the light DOM, passed to the select inside through the default slot and read by it as data (web-options.md).	The select's own option, under the same name: the select field passes it to its select and reads nothing of it.	The select's own option, under the same name: the select field passes it to its select and reads nothing of it.	The select's own option, under the same name: the select field passes it to its select and reads nothing of it.	The select's own option, under the same name: the select field passes it to its select and reads nothing of it.

option-group · group — holds items

A run of related options, optionally titled. The select separates a group from what is next to it by a divider or a gap.

Property	Type	Default	Description
title	string	""	A short heading drawn above the group's options, which also names the group; empty draws none and leaves the group unnamed.

Spec	Web	SwiftUI	Jetpack Compose	Flutter	React Native
Item	tanrei-option-group	TanreiSelectSection	TanreiSelectGroup	TanreiSelectGroup	SelectOptionGroup
title · Property	label	title	title	title	title
Notes	As the option: the same element, the product's child, with its options inside it.	The select's own option group, under the same name: the select field passes it to its select and reads nothing of it.	The select's own option group, under the same name: the select field passes it to its select and reads nothing of it.	The select's own option group, under the same name: the select field passes it to its select and reads nothing of it.	The select's own option group, under the same name: the select field passes it to its select and reads nothing of it.

States

Behavior

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

ID	Requirement
SEF-1	THE select field SHALL be a Field that frames one select, 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 select, each unchanged; SHALL hold the label-icon slot for its Field and the leading-icon slot for its select; SHALL give its select every option and option group the product gives it, in the order given, as that select's own items, read, drawn and chosen by the select (SEL-17, SEL-31 to SEL-45); and SHALL emit its select's events as its own, each once. 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 select do when a product places the one in the other (FLD-1 to FLD-28; SEL-1 to SEL-64) — 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, SEL-15, SEL-7); the supporting row and the error, started where the value starts (FLD-7 to FLD-9, FLD-26); the rows drawn focused while the list is open (FLD-13, SEL-20); the name, the description and the states (FLD-10, FLD-11, FLD-14, SEL-11); and the width, which is the Field's and which the select fills (FLD-1, SEL-49).
SEF-2	WHERE the platform has forms (the web) THE select field SHALL be the one control the form sees: it SHALL take name, submit its select's value, reset to the value it was first given, restore it on navigation, report to the form's constraint validation exactly what its select would report there (SEL-11), be submitted WHILE readOnly is true (SEL-47), and be left out WHILE disabled is true or a disabled group of the form holds it (SEL-46); its select and its Field SHALL take no part in the form themselves.
SEF-3	WHEN the select field is given focus — by the product, by a press on its label row (FLD-12), or by a form that reports its validity — THE select field SHALL pass the focus to its select's container and SHALL add no stop to the focus order: the one stop inside it is its select's (SEL-13). WHILE focus is anywhere inside it, or its select's list is open, THE select field SHALL count as focused for its Field (FLD-13).
SEF-4	IF the select field is placed in a Field THE select field SHALL in debug builds report that it is a field already and that the bare control is the select, and both SHALL still render (FLD-15). WHILE it stands in a field group THE select field SHALL follow that group's disabled, through its own Field, and take nothing else from the group (FGR-20).
SEF-5	THE select field SHALL have no words of its own and SHALL read none: requiredText and optionalText are read by its Field (FLD-24), emptyText by its select (SEL-62), each from the instance's prop and then from the product's words.
SEF-6	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 select 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 select field is invalid — except those the select field owns (aria-label, aria-labelledby, aria-disabled, aria-haspopup, aria-expanded, aria-controls), which it SHALL move and not expose: its name is label (SEF-1). 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 select field SHALL take it off that element. WHEN the product sets an aria- attribute the select field owns THE select 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-select-field	TanreiSelectField	TanreiSelectField	TanreiSelectField	SelectField
variant · Property	variant	variant	variant	variant	variant
size · Property	size	size	size	size	size
value · Property	value	selection	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
open · Property	open	isPresented	expanded	controller	open
separation · Property	separation	separation	separation	separation	separation
iconSpace · Property	iconSpace	iconSpace	iconSpace	iconSpace	iconSpace
density · Property	density	density	density	density	density
status · Property	status	status	status	status	status
statusText · Property	statusText	statusText	statusText	statusText	statusText
emptyText · Property	emptyText	emptyText	emptyText	emptyText	emptyText
change · Event	change	selection	onValueChange	onChanged	onValueChange
toggle · Event	toggle	isPresented	onExpandedChange	onOpenChanged	onOpenChange
Notes	The tag tanrei-select-field, the class TanreiSelectField, the React name SelectField. It takes every attribute, property, event and child of the select and of its Field, under the same names. The element is composed as every field element is; what follows is what is particular to it. Members: <tanrei-field> holding one <tanrei-select> in its default slot; the product places none, and gives the options. The host is display: block, as the Field is. Value member: tanrei-select. The host is the form's element — name, the value and its state, validity anchored on the select's trigger, reset to the value attribute, restore, form, a disabled fieldset — and the select inside has no name. 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 select: variant, size, value, placeholder, readOnly, open, separation, iconSpace, status, statusText, emptyText, and inline, the select's attribute for tests and fixtures, which is no prop of the spec and is passed on so that an open fixture and its twin are staged alike. Attributes are the members' own: kebab-case, except readonly. Props of one name on both members — label, labelHidden, error, disabled — are the Field's; the select's are never set by the element and reach the select through the connection. Events: change is the select's own composed, bubbling Event and leaves by itself with the host as its target. toggle is the select's CustomEvent, composed and not bubbling: it is heard on the host, as on any shadow host, and by no ancestor. Two props are the select's at every moment and are read through to it, never copied — value (the element's value is its value member's) and open, by the same accessor, as the combobox field reads its three — so each is already new in every listener of change and of toggle, capturing or bubbling, and when open is taken back with no event. No listener of the element's takes either. None is stopped and none is copied. Slots: label-icon is passed to the Field and leading-icon to the select, each by a slot element of the same name rendered only while the host has a child for it. The default slot is passed to the select — <tanrei-select><slot></slot></tanrei-select> — and is always rendered, where a field element otherwise has no default slot: the product's <tanrei-option> and <tanrei-option-group> children are assigned to it, and the select reads them through it. A child that is neither, and has no slot name the element has, is not rendered and is reported in a debug build. Parts: the member hosts are field and select. Exported from the Field: label, label-icon, requirement-label, supporting-text, counter (never drawn here). Exported from the select: container, outline, active-indicator, label, requirement-label, value, placeholder, leading-icon, chevron, list, option, option-label, option-supporting-text, option-leading-icon, mark, group, group-title, divider, status. Two names collide, label and requirement-label. Each is exported with its member's name before it, always (field-label, select-label, field-requirement-label, select-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. Focus: the shadow root does not delegate. focus() and blur() call the select's; a press on the label row focuses the trigger by FLD-12 and opens nothing, a press on the trigger opens the list, and a press on the help does nothing. The list is the select's own popover in the top layer: it is placed against the trigger, both in the select's shadow tree, and a press on the Field's rows is a press outside it (SEL-27). The connection is the Field's with its control, with one value more upward, drawnFocused (SEL-63, FLD-13), the same value the combobox says; 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-* and --tanrei-comp-select-* reach the members by inheritance, and one select 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="Country" required supporting-text="Where your invoices are addressed."><tanrei-select name="country" value="jp"><tanrei-option value="jp">Japan</tanrei-option></tanrei-select></tanrei-field>. Before the element is defined its options are running text in the page, as a select's are: hide tanrei-select-field:not(:defined) > * and reserve the block size. Words: none of its own; required-text and optional-text left empty are read by the Field from the product's words.	TanreiSelectField("Country", selection: $country, supportingText: "…") { TanreiSelectOption("Japan").tag("jp") … }: a view whose body is TanreiField(…) { TanreiSelect(selection:) { options } } with each argument passed to the member it is from, and nothing else. The option content is the select's own, passed through as a view builder. labelHidden follows .labelsHidden() and disabled follows .disabled(_:), both read by the Field. The product's words are read by the Field from the \.tanreiWords environment value. Not built on this platform yet, nor is the select itself.	TanreiSelectField(value, onValueChange, label, supportingText = …) { TanreiSelectOption("Japan", "jp") … }: a composable that calls TanreiField(…) { TanreiSelect(…) { content() } } with each argument passed to the member it is from, and nothing else; the content lambda is the select's. enabled is the inverse flag and isError keeps Compose's name, both the Field's. The product's words are read by the Field from LocalTanreiWords. Not built on this platform yet, nor is the select itself.	TanreiSelectField(value:, onChanged:, labelText:, helperText:, options: […]): a widget that builds TanreiField(child: TanreiSelect(…)) with each argument passed to the member it is from, and nothing else; labelText, hintText, helperText, errorText and enabled keep InputDecoration's names. TanreiSelectFormField wraps it as a FormField<String> (validator, onSaved, autovalidateMode), which is how a Flutter form takes part, and its errorText is the Field's. The product's words are read by the Field from the TanreiWords inherited widget. Not built on this platform yet, nor is the select itself.	<SelectField label="Country" value={value} onValueChange={setValue} supportingText="…" options={[…]} />: a component that renders <Field …><Select … /></Field> with each prop passed to the member it is from, and nothing else; options is the select's array. The product's words are read by the Field from the TanreiWordsProvider context. Not built on this platform yet, nor is the select itself.

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 (41)

stacked-empty

variant: stacked label: Country items: 5

stacked-value

variant: stacked value: jp label: Country items: 5

stacked-open

variant: stacked value: jp label: Country open: true items: 5 Drawn alone in a window of 312 × 472

stacked-large

variant: stacked size: large value: jp label: Country items: 5

stacked-small

variant: stacked size: small value: jp label: Country items: 5

stacked-error

variant: stacked label: Country errorText: Choose a country. error: true items: 5

stacked-disabled

variant: stacked value: jp label: Country disabled: true items: 5

stacked-placeholder

label: Country placeholder: Choose a country items: 5

stacked-open-none-chosen

label: Country placeholder: Choose a country open: true items: 5 Drawn alone in a window of 312 × 473

stacked-label-hidden

value: fr label: Country labelHidden: true items: 5

stacked-supporting

value: jp label: Country supportingText: Where your invoices are addressed. items: 5

stacked-error-value

value: ke label: Country errorText: We cannot ship there yet. error: true items: 5

stacked-read-only

value: jp label: Country readOnly: true items: 5

stacked-required

label: Country required: true requiredText: Required items: 5

stacked-optional

label: Country placeholder: Choose a country optional: true optionalText: Optional items: 5

stacked-required-asterisk

label: Country required: true requiredMark: asterisk items: 5

stacked-required-disabled

value: jp label: Country disabled: true required: true requiredText: Required items: 5

stacked-required-error

label: Country errorText: Choose a country. error: true required: true requiredText: Required items: 5

stacked-required-ja

label: 国 placeholder: 国を選択 required: true requiredText: 必須 items: 3

stacked-optional-ja

value: jp label: 国 optional: true optionalText: 任意 items: 3

stacked-label-icon

value: Asia/Tokyo label: Time zone items: 3 slots: label-icon

stacked-option-icon

value: dark label: Theme items: 3

stacked-leading-icon

value: ja label: Language items: 2 slots: leading-icon

open-icons

value: dark label: Theme open: true items: 3 Drawn alone in a window of 312 × 473

open-supporting-text

value: team label: Plan open: true items: 3 Drawn alone in a window of 312 × 473

open-disabled-chosen

value: enterprise label: Plan open: true items: 3 Drawn alone in a window of 312 × 473

open-groups

value: Europe/Lisbon label: Time zone open: true items: 3 Drawn alone in a window of 312 × 473

open-groups-divider

value: Europe/Lisbon label: Time zone open: true separation: divider items: 3 Drawn alone in a window of 312 × 473

open-groups-gap

value: Europe/Lisbon label: Time zone open: true separation: gap items: 3 Drawn alone in a window of 312 × 473

open-many

value: corner.small label: Token open: true items: 24 Drawn alone in a window of 312 × 473

open-long-options

value: weekly label: Email me open: true items: 3 Drawn alone in a window of 312 × 473

long-value

value: all label: Email me items: 3

empty-value-option

value: label: Contrast items: 3

small-label-hidden

size: small value: high label: Contrast labelHidden: true items: 3

small-label-hidden-icons

size: small value: light label: Theme labelHidden: true items: 3

small-label-hidden-leading-icon

size: small value: en label: Language labelHidden: true items: 2 slots: leading-icon

small-label-hidden-open

size: small value: light label: Theme labelHidden: true open: true items: 3 Drawn alone in a window of 312 × 473

small-open

size: small value: jp label: Country open: true items: 5 Drawn alone in a window of 312 × 473

stacked-required-rtl

value: Asia/Tokyo label: المنطقة الزمنية supportingText: تُعرض المواعيد بهذا التوقيت. required: true requiredText: مطلوب direction: rtl items: 2 slots: label-icon

open-rtl

value: Asia/Tokyo label: المنطقة الزمنية open: true direction: rtl items: 2 Drawn alone in a window of 312 × 473

long-value-rtl

value: all label: Email me direction: rtl items: 3

variant: filled (7)

filled-empty

variant: filled label: Country items: 5

filled-value

variant: filled value: jp label: Country items: 5

filled-open

variant: filled value: jp label: Country open: true items: 5 Drawn alone in a window of 312 × 473

filled-large

variant: filled size: large value: jp label: Country items: 5

filled-small

variant: filled size: small value: jp label: Country items: 5

filled-error

variant: filled label: Country errorText: Choose a country. error: true items: 5

filled-disabled

variant: filled value: jp label: Country disabled: true items: 5

variant: outlined (9)

outlined-empty

variant: outlined label: Country items: 5

outlined-value

variant: outlined value: jp label: Country items: 5

outlined-open

variant: outlined value: jp label: Country open: true items: 5 Drawn alone in a window of 312 × 473

outlined-large

variant: outlined size: large value: jp label: Country items: 5

outlined-small

variant: outlined size: small value: jp label: Country items: 5

outlined-error

variant: outlined label: Country errorText: Choose a country. error: true items: 5

outlined-disabled

variant: outlined value: jp label: Country disabled: true items: 5

outlined-required

variant: outlined label: Country required: true requiredText: Required items: 5

outlined-rtl

variant: outlined value: Europe/Lisbon label: المنطقة الزمنية direction: rtl items: 2

Generated from specs/select-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-select> in it, and nothing else. Importing the element defines both.
• The options stay your children of <tanrei-select-field>. They are never moved or copied: they reach the select inside through a slot, and the select reads them again when they change. Replacing them by hand (replaceChildren()) works as on a select.
• The element is form-associated. It takes name and form, submits the value alone — nothing while disabled, and still while read-only —, resets to the value attribute, follows a disabled <fieldset>, and reports a missing value while required is set and the value is empty. Its two members add no entry to the form.
• change is the select’s composed, bubbling event. toggle is the select’s CustomEvent with detail.open and detail.reason: composed, and not bubbling, so it is heard on the element and never by an ancestor such as a <details>. Their target is the element, and event.target.value and event.target.open are new in every listener.
• Parts: field and select are the two members. Their own parts have the same names here as one level down: label-icon, supporting-text; container, outline, active-indicator, value, placeholder, leading-icon, chevron, list, option, option-label, option-supporting-text, option-leading-icon, mark, group, group-title, divider, status. label and requirement-label are the drawn one of the two — the field’s row, or the select’s floating label — and field-label, select-label, field-requirement-label and select-requirement-label name one member’s alone.
• The element is not focusable itself: focus() goes to the trigger, and a page’s own <label for> moves focus there. A press on the label row focuses the trigger and opens nothing; a press on the trigger opens the list; a press on the help does nothing.
• The element has no role. Name it with label — with label-hidden where the label is drawn elsewhere — and never with aria-label, which names nothing here.
• The attributes are the members’ own: label-hidden, supporting-text, error-text, required-mark, required-text, optional-text, readonly.
• A child that is neither an option, a group of options nor a glyph for label-icon or leading-icon is not drawn; a debug build says so.
• Before the element is defined, its options are running text. Hide tanrei-select-field:not(:defined) > * and reserve the height. A page that must work without script uses a native <select> with its own <label>.

Guidelines

link

Do

link

• Write a label that names what is chosen, and keep it visible in a form.
• Order options the way people look for them: alphabetically, by number, or the common ones first.
• Group a long list and give each group a short title.
• Preselect a value only where most people would choose it.
• Give the field a width by its place: a column of a form. The box fills it.

Don’t

link

• Don’t use a select field with labelHidden in a bar or a toolbar. That is the bare select, named by its own label.
• Don’t use the placeholder as the label. It goes away once something is chosen.
• Don’t navigate, submit or delete on change without saying so. People move through a list to read it.
• Don’t put a select field inside a field. It is a field already; a debug build says so. The control a field frames is the select.
• Don’t name it with aria-label. Where no label should be drawn, give label and labelHidden.

Accessibility

link

Role

combobox

Labeling

The select field adds nothing to what its members expose and coordinates nothing: the Field gives the select its name, its description and its required, invalid and disabled states (FLD-8, FLD-10, FLD-11, FLD-14), and the select carries them on its own trigger and names its list by the same name (SEL-11, SEL-48). Assistive technology meets one control that opens a list of choices, named by label, with the chosen option's label as its value — exactly as it meets a Field around a select 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 select's (its accessibility block; SEL-23, SEL-27, SEL-28, SEL-31, SEL-33, SEL-34). The select field handles no key and adds no focus stop (SEF-3).

Notes

• One level down is the same thing: a Field with a select in it, holding the same options. Every fixture has that pair as its twin, and the accessibility tree of the two is the same (SEF-1).
• On the web the two members stand in the select field's own shadow root, so the form meets the select field and not the select (SEF-2), focus passes through to the trigger (SEF-3), and the options, which stay the product's children, reach the select through a slot and are read by it as data.
• A select with no visible label of its own — in a header, a toolbar, a column of a table — is the bare select, named by its own label, not a select field with labelHidden.

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

What the component handles

link

• It is one combobox that is not editable, the select’s. Its name is label, drawn or not; its description is the shown supporting or error text, with the optional text while the field is optional.
• It is exposed as invalid while error is true, as required while required is set, as disabled while disabled is true, as read-only while readOnly is true, and as expanded while its list is open.
• The name, the description and the states are tied exactly as a field ties them to any control it frames. The field written by hand, one level down, is the same control.
• The drawn label, the requirement mark and the glyphs are not exposed a second time.
• It is one stop for the Tab key. A press on the label moves focus to the trigger and opens nothing; a press on the help does nothing.
• An error that appears while focus is in the select field is announced once, politely, by its field member.
• Everything in the list — the active option, the options’ names, descriptions and states, the groups — is the select’s, as on the select’s page.
• Direction, enlarged text and forced colors are each member’s own answer.
• It has no words of its own. requiredText and optionalText left empty are read from the product’s words by the field.

Known gaps on the web are its members’: the divider between two groups is not exposed as a separator, typing compares labels the way JavaScript does, and before the element is defined nothing is drawn but the options as text.

What you need to do

link

• Give every select field a label, and every option a label.
• Validate the value yourself, set error, and write errorText so that it says how to put the answer right.
• Give the words of the requirement: required-text and optional-text on the select field, or once for the whole product with setWords({ requiredText, optionalText }). Tanrei ships none: without requiredText an asterisk stands in the tag’s place, and without optionalText no tag is drawn and nothing is said. See The product’s words.
• Keep option values unique within a select field.