Constants & Enums

Kraken TUI exports several constant objects and enums for use in event handling, animation, theming, and accessibility.

Animation Constants

AnimProp

Animation property identifiers for Widget.animate().

import { AnimProp } from "kraken-tui";

Constant	Value	Description
`AnimProp.Opacity`	`0`	Widget opacity (0.0 to 1.0)
`AnimProp.FgColor`	`1`	Foreground color (RGB)
`AnimProp.BgColor`	`2`	Background color (RGB)
`AnimProp.BorderColor`	`3`	Border color (RGB)
`AnimProp.PositionX`	`4`	X offset for position animation
`AnimProp.PositionY`	`5`	Y offset for position animation

Example

// Fade out animation
widget.animate(AnimProp.Opacity, 0.0, 500, Easing.EaseOut);

// Position animation
widget.animate(AnimProp.PositionX, 100, 300, Easing.EaseInOut);

Easing

Easing function identifiers for animations.

import { Easing } from "kraken-tui";

Constant	Value	Description
`Easing.Linear`	`0`	Constant speed throughout
`Easing.EaseIn`	`1`	Slow start, accelerates
`Easing.EaseOut`	`2`	Fast start, decelerates
`Easing.EaseInOut`	`3`	Slow start and end, fast middle
`Easing.CubicIn`	`4`	Cubic acceleration
`Easing.CubicOut`	`5`	Cubic deceleration
`Easing.Elastic`	`6`	Elastic bounce effect
`Easing.Bounce`	`7`	Bouncing effect

Example

// Smooth ease-in-out
widget.animate(AnimProp.Opacity, 0.5, 400, Easing.EaseInOut);

// Bouncy animation
widget.animate(AnimProp.PositionY, 50, 600, Easing.Bounce);

Easing functions are implemented in the Rust core. See Animation Concepts for visual curves.

Event Constants

EventType

Event type identifiers.

import { EventType } from "kraken-tui";

Constant	Value	Description
`EventType.None`	`0`	No event (sentinel)
`EventType.Key`	`1`	Keyboard event
`EventType.Mouse`	`2`	Mouse event (click, scroll)
`EventType.Resize`	`3`	Terminal resize
`EventType.FocusChange`	`4`	Focus gained/lost
`EventType.Change`	`5`	Widget value changed
`EventType.Submit`	`6`	Form submitted
`EventType.Accessibility`	`7`	Accessibility event

Example

for (const event of app.drainEvents()) {
  if (event.type === "key" || event.eventType === EventType.Key) {
    console.log("Keyboard event");
  }
}

The KrakenEvent object has both a string type field and a numeric eventType field. Use whichever is more convenient.

KeyCode

Special key code constants (non-printable keys).

import { KeyCode } from "kraken-tui";

Constant	Value	Key
`KeyCode.Backspace`	`0x0100`	Backspace
`KeyCode.Enter`	`0x0101`	Enter/Return
`KeyCode.Left`	`0x0102`	Left arrow
`KeyCode.Right`	`0x0103`	Right arrow
`KeyCode.Up`	`0x0104`	Up arrow
`KeyCode.Down`	`0x0105`	Down arrow
`KeyCode.Home`	`0x0106`	Home
`KeyCode.End`	`0x0107`	End
`KeyCode.PageUp`	`0x0108`	Page Up
`KeyCode.PageDown`	`0x0109`	Page Down
`KeyCode.Tab`	`0x010a`	Tab
`KeyCode.BackTab`	`0x010b`	Shift+Tab
`KeyCode.Delete`	`0x010c`	Delete
`KeyCode.Insert`	`0x010d`	Insert
`KeyCode.Escape`	`0x010e`	Escape
`KeyCode.F1`	`0x0110`	F1 function key

Printable character keys (letters, numbers, symbols) use their Unicode codepoints directly. Only special keys use these 0x0100+ constants.

Example

// Check for Escape key
if (event.keyCode === KeyCode.Escape) {
  running = false;
}

// Check for Enter key
if (event.keyCode === KeyCode.Enter) {
  submitForm();
}

// Check for printable character
if (event.keyCode === 0x51) { // 'Q'
  quit();
}

Modifier

Keyboard modifier flags (bitfield).

import { Modifier } from "kraken-tui";

Constant	Value	Description
`Modifier.Shift`	`0x01`	Shift key held
`Modifier.Ctrl`	`0x02`	Control key held
`Modifier.Alt`	`0x04`	Alt/Option key held
`Modifier.Super`	`0x08`	Super/Windows/Command key held

Example

// Check for Ctrl+C
if (event.keyCode === 0x43 && event.modifiers & Modifier.Ctrl) {
  handleCopy();
}

// Check for Shift+Tab
if (event.keyCode === KeyCode.Tab && event.modifiers & Modifier.Shift) {
  focusPrevious();
}

// Check for multiple modifiers (Ctrl+Shift+S)
if (event.keyCode === 0x53 && 
    (event.modifiers & Modifier.Ctrl) && 
    (event.modifiers & Modifier.Shift)) {
  saveAs();
}

Modifier values are bitflags. Use bitwise AND (&) to check if a modifier is active, not equality (===).

NodeType

Widget type identifiers (used internally by the FFI).

import { NodeType } from "kraken-tui";

Constant	Value	Widget Class
`NodeType.Box`	`0`	`Box`
`NodeType.Text`	`1`	`Text`
`NodeType.Input`	`2`	`Input`
`NodeType.Select`	`3`	`Select`
`NodeType.ScrollBox`	`4`	`ScrollBox`
`NodeType.TextArea`	`5`	`TextArea`

You generally don’t need to use NodeType directly in application code. It’s primarily used internally by the FFI layer.

Accessibility Constants

AccessibilityRole

Accessibility role identifiers for assistive technologies.

import { AccessibilityRole } from "kraken-tui";

Constant	Value	Description
`AccessibilityRole.Button`	`0`	Button or clickable element
`AccessibilityRole.Checkbox`	`1`	Checkbox or toggle
`AccessibilityRole.Input`	`2`	Text input field
`AccessibilityRole.TextArea`	`3`	Multi-line text input
`AccessibilityRole.List`	`4`	List container
`AccessibilityRole.ListItem`	`5`	Item within a list
`AccessibilityRole.Heading`	`6`	Section heading
`AccessibilityRole.Region`	`7`	Landmark region
`AccessibilityRole.Status`	`8`	Status or live region

Example

import { AccessibilityRole } from "kraken-tui";

// Mark widget as a button
widget.setRole(AccessibilityRole.Button);
widget.setLabel("Submit");

// Mark heading
header.setRole(AccessibilityRole.Heading);
header.setLabel("Settings");

Use accessibility roles with setLabel() and setDescription() to improve screen reader support. See Advanced Patterns for more.

Theme Constants

DARK_THEME

Handle for the built-in dark theme.

import { DARK_THEME } from "kraken-tui";

app.switchTheme(DARK_THEME);

Value: 1

LIGHT_THEME

Handle for the built-in light theme.

import { LIGHT_THEME } from "kraken-tui";

app.switchTheme(LIGHT_THEME);

Value: 2

These constants represent theme handles. The actual theme definitions are built into the Rust core.

Performance Counter IDs

PERF_ACTIVE_ANIMATIONS

Performance counter ID for the number of active animations.

import { PERF_ACTIVE_ANIMATIONS } from "kraken-tui/loop";

const count = app.getPerfCounter(PERF_ACTIVE_ANIMATIONS);
console.log(`${count} animations running`);

Value: 6 See Kraken.getPerfCounter() for usage.

Usage Patterns

Import Only What You Need

// Specific imports
import { KeyCode, Modifier } from "kraken-tui";

// Use directly
if (event.keyCode === KeyCode.Enter) { /* ... */ }

Type-Safe Constant Objects

All constant objects are defined with as const to ensure type safety:

// This is type-safe
const prop: AnimProp = AnimProp.Opacity; // ✓

// This would fail type checking
const invalid: AnimProp = 99; // ✗ Type error

Bitfield Operations

For modifier flags:

// Check if Ctrl is pressed
if (event.modifiers & Modifier.Ctrl) { /* ... */ }

// Check if NO modifiers are pressed
if (event.modifiers === 0) { /* ... */ }

// Check if ONLY Shift is pressed
if (event.modifiers === Modifier.Shift) { /* ... */ }

// Check if Ctrl OR Alt is pressed
if (event.modifiers & (Modifier.Ctrl | Modifier.Alt)) { /* ... */ }

Source References

Animation constants: ts/src/animation-constants.ts
Event/Widget constants: ts/src/ffi/structs.ts
Loop constants: ts/src/loop.ts
Theme constants: ts/src/theme.ts

Animation

Widget animation methods

Event Handling

Working with events

Themes

Theme customization

Accessibility

Accessibility methods

Core API

Widgets

JSX & Reactivity

Reference

Constants & Enums

Constants & Enums

Animation Constants

AnimProp

Example

Easing

Example

Event Constants

EventType

Example

KeyCode

Example

Modifier

Example

Widget Constants

NodeType

Accessibility Constants

AccessibilityRole

Example

Theme Constants

DARK_THEME

LIGHT_THEME

Performance Counter IDs

PERF_ACTIVE_ANIMATIONS

Usage Patterns

Import Only What You Need

Type-Safe Constant Objects

Bitfield Operations

Source References

Animation

Event Handling

Themes

Accessibility

Build docs developers (and LLMs) love

Core API

Widgets

JSX & Reactivity

Reference

​Constants & Enums

​Animation Constants

​AnimProp

​Example

​Easing

​Example

​Event Constants

​EventType

​Example

​KeyCode

​Example

​Modifier

​Example

​Widget Constants

​NodeType

​Accessibility Constants

​AccessibilityRole

​Example

​Theme Constants

​DARK_THEME

​LIGHT_THEME

​Performance Counter IDs

​PERF_ACTIVE_ANIMATIONS

​Usage Patterns

​Import Only What You Need

​Type-Safe Constant Objects

​Bitfield Operations

​Source References

​Related APIs

Animation

Event Handling

Themes

Accessibility

Build docs developers (and LLMs) love

Constants & Enums

Animation Constants

AnimProp

Example

Easing

Example

Event Constants

EventType

Example

KeyCode

Example

Modifier

Example

Widget Constants

NodeType

Accessibility Constants

AccessibilityRole

Example

Theme Constants

DARK_THEME

LIGHT_THEME

Performance Counter IDs

PERF_ACTIVE_ANIMATIONS

Usage Patterns

Import Only What You Need

Type-Safe Constant Objects

Bitfield Operations

Source References

Related APIs