components / textarea

Textarea

Multiline field built on the same DK field contract as TextField, with containment checks for longer content.

Overview

What it is

This section explains the intent of the component before the implementation details.

  • Textarea extends the field shell to multiline content while preserving the same labeling, helper, and error contract as TextField.
  • Use it for summaries, notes, and descriptions where line breaks are part of the user’s input.

Aliases

multiline input

Decision guide

How to choose it

Use these notes to decide quickly whether this is the right DK component for the job.

Decision guide

  • Choose Textarea when the interaction should feel deliberate, documented, and reusable across product surfaces.
  • If the scenario is more specialized than the current Textarea contract, prefer a simpler component or build a dedicated workflow on top of the lower-level DK primitives.

Do

  • Keep the Textarea label, value, or status language direct enough to scan quickly.
  • Use the documented size and state recipes instead of inventing one-off variants in product code.

Do not

  • Do not hide the main purpose of Textarea behind decorative copy or overloaded surface treatments.
  • Do not stretch Textarea into a workflow it was not designed to handle just because the visuals are close.

Usage

When to use

Prefer these situations when choosing this component.

  • Use Textarea when the user is entering multi-line content with predictable height.
  • Keep helper or error text close so the field’s purpose and state remain obvious.

Usage

When not to use

These patterns are better served by a different component or a simpler surface.

  • Do not use Textarea for single-line identifiers or short values.
  • Do not turn it into an auto-growing editor in this v1 contract.

Anti-patterns

  • Using Textarea as a generic layout container instead of a purpose-built interaction or content surface.
  • Forking the documented recipe in product code instead of extending the shared DK contract.

Migration notes

  • Migrate legacy textarea usage by mapping existing variants and states onto the documented DK props before porting any custom styling.
  • Treat the docs examples as the reference contract for accessibility and event behavior during adoption.

Anatomy

Structural parts

The anatomy explains which pieces matter to the recipe and accessibility model.

field wrapper

root

Carries label, helper text, and validation messaging.

field label

label

Names the content being collected.

native textarea

control

Multiline text entry area.

API

Public interface

The docs contract distinguishes props, DOM events, and slots so integration behavior is explicit.

Props

NameTypeDefaultDescription
labelstring—Visible label used for the field or control.
descriptionstring—Supporting helper copy rendered below or beside the main label.
errorstring—Validation or problem copy rendered in the error slot when present.
placeholderstring—Placeholder text shown before a user makes a selection or enters text.
requiredbooleanfalseMarks the field or control as required for form semantics and docs examples.
disabledbooleanfalseDisables interaction and exposes the correct non-interactive semantics for the control.
namestring—Form field name used for native form submission.
idstring—Optional id used to bind external labels or descriptions to the component.
size'sm' | 'md' | 'lg''md'Chooses the compiled size recipe for the component.
valuestring—Controlled textarea value.
rowsnumber4Visible line count for the textarea.
resize'none' | 'vertical' | 'both''vertical'Controls user resizing when enabled by the browser.
onChange(detail: { value: string | undefined }) => void—Callback fired when the value changes.
themeThemeContract—Overrides the compiled DK theme used to resolve tokens and recipes for this component.

Events

NamePayloadDescription
change{ value: string | undefined }Fires when the component commits a new value.

Slots

NameDescription
defaultTextarea is prop-driven in v1 and does not expose content slots.

Recipes

Variants, sizes, and states

These notes summarize the intended recipe surface rather than exposing raw implementation detail first.

Variants

  • default: Textarea uses one multiline shell and varies mainly by size and rows.

Sizes

  • sm: Compact multiline field.
  • md: Default multiline field.
  • lg: Larger multiline field for spacious layouts.

States

  • rest: Default multiline shell.
  • focus-visible: Focused state with visible keyboard treatment.
  • invalid: Validation state with error copy.
  • disabled: Semantically disabled and visibly muted.

Accessibility

Accessibility contract

This is the behavior the component promises to assistive tech and keyboard users today.

Semantics

  • Uses standard field labeling through visible labels, descriptions, and error text.
  • Exposes disabled and required semantics through the underlying form control.

Keyboard

  • Supports native focus and text entry behavior.
  • Supports native multiline editing, selection, and navigation behavior.

Screen readers

  • Connects visible label, helper text, and error text to the native control.

Checklist

  • Verify the visible label or title still produces a clear accessible name.
  • Verify focus remains obvious in every supported state and size.
  • Verify disabled, selected, and error states do not rely on color alone.

Implementation

Tokens and slot vars

This section shows the representative compiled slot variables that the runtime consumes for the selected design system.

root

--dk-field-stack-gap
0.45rem

label

--dk-field-label-color
#16181c
--dk-field-label-size
clamp(1.333rem, 1.2222rem + 0.494vw, 1.667rem)
--dk-field-label-weight
600

field

--dk-textarea-bg
#f2f5fb
--dk-textarea-fg
#16181c
--dk-textarea-border
#95989d
--dk-textarea-border-width
1px
--dk-textarea-radius
clamp(0.75rem, 0.6875rem + 0.278vw, 0.938rem)
--dk-textarea-block-size
136px
--dk-textarea-inline-padding
clamp(1.333rem, 1.2222rem + 0.494vw, 1.667rem)
--dk-textarea-block-padding
clamp(1.333rem, 1.2222rem + 0.494vw, 1.667rem)
--dk-textarea-font-size
clamp(1.333rem, 1.2222rem + 0.494vw, 1.667rem)
--dk-textarea-placeholder
#95989d
--dk-textarea-shadow
none
--dk-textarea-focus-ring-color
#2072e4
--dk-textarea-motion-duration
200ms

description

--dk-field-description-color
#16181c
--dk-field-description-size
0.8125rem

error

--dk-field-error-color
#cc272e
--dk-field-error-size
0.8125rem

Implementation notes

  • Textarea deliberately avoids auto-grow in v1 so height behavior stays predictable and testable.

Implementation checklist

  • Use the public component API first and only drop to lower-level primitives when the component contract genuinely does not fit.
  • Keep theme overrides token-driven so proofs and recipes stay meaningful.
  • Verify the shipped examples and proof fixtures still represent the real product scenario you are implementing.

Examples

Copy-paste examples

Each example is intentionally practical, grouped by starter, common pattern, and edge-case coverage.

Examples
3
Depth
baseline

Starter

1 example

starter

Starter: summary field

A labeled multiline field for short summaries.

Copy snippet

<Textarea label="Summary" description="Share the launch highlights." placeholder="Type the short summary." rows={4} />

Common patterns

1 example

common

Common: compact multiline field

Smaller size works well in inspector-style tools.

Copy snippet

<Textarea size="sm" label="Internal note" rows={3} />

Edge cases

1 example

edge

Edge: required narrative input

Use explicit error copy when the narrative field is mandatory.

Copy snippet

<Textarea label="Summary" error="Add a short summary before publishing." rows={5} />

Verification

Curated proof fixtures

Proofs stay visible in the docs so the system shows what it can guarantee, not just what it can render.

default (size=sm)

pass

size=sm

  • Contrast: 98.5 Lc
  • Target: 44px
  • Layout: 513 / 260, 340, 440
  • Helper: 2/2

default (size=md)

pass

size=md

  • Contrast: 98.5 Lc
  • Target: 44px
  • Layout: 666 / 260, 340, 440
  • Helper: 2/2

default (size=lg)

pass

size=lg

  • Contrast: 98.5 Lc
  • Target: 44px
  • Layout: 887 / 260, 340, 440
  • Helper: 2/2

invalid (size=sm)

pass

size=sm

  • Contrast: 98.5 Lc
  • Target: 44px
  • Layout: 513 / 260, 340, 440
  • Helper: 2/2

invalid (size=md)

pass

size=md

  • Contrast: 98.5 Lc
  • Target: 44px
  • Layout: 666 / 260, 340, 440
  • Helper: 2/2

invalid (size=lg)

pass

size=lg

  • Contrast: 98.5 Lc
  • Target: 44px
  • Layout: 887 / 260, 340, 440
  • Helper: 2/2