Utility Types

Utility TypeScript types exported from @ndriadev/react-tools.

import type { ... } from '@ndriadev/react-tools'

---

NestedKeyOf

• @template T - A record type whose keys are strings or numbers. *

Constructs a union of dot-separated path strings representing all reachable properties and nested properties of T.

export type NestedKeyOf<T extends Record<string, unknown>> =
	{ [Key in keyof T & (string | number)]: T[Key] extends Record<string, unknown>
		? `${Key}.${NestedKeyOf<T[Key]>}`
		: `${Key}`
	}[keyof T & (string | number)];

ErrorModel

• @template T - An object type to mirror. *

Constructs a mirrored type from T where every property — including nested ones — is replaced with boolean. Useful for representing validation error maps that track which fields are invalid.

export type ErrorModel<T extends object> = {
	[k in keyof T]: T[k] extends object ? ErrorModel<T[k]> : boolean;
};

SelectivePartial

• @template T - The base object type.
• @template E - A union of keys from T to make optional. *

Constructs a type identical to T except that the properties listed in E are made optional. All other properties remain required.

export type SelectivePartial<T extends object, E extends keyof T> =
	Omit<T, E> & Partial<Pick<T, E>>;

RecursivePartial

• @template T - The object type to make recursively partial. *

Constructs a deeply partial version of T, making every property and every nested property optional. Analogous to Partial<T> but applied recursively.

export type RecursivePartial<T extends object> = {
	[K in keyof T]?: T[K] extends object ? RecursivePartial<T[K]> : Partial<T[K]>;
};

Optional

• @template T - The primary value type.
• @template E - The alternative type. Defaults to null. *

Constructs a type that is either T or E. Defaults to T | null when E is not specified. A semantic alias for nullable or alternative value types.

export type Optional<T = unknown, E = null> = T | E;

DependencyListTyped

• @template T - The type of each dependency element. Defaults to unknown. *

A strictly-typed variant of React's DependencyList. Behaves identically to ReadonlyArray<unknown> but allows the element type to be narrowed to T, enabling compile-time checking of dependency types in custom hooks such as {@link useCallbackCompare} and {@link useMemoCompare}.

export type DependencyListTyped<T = unknown> = ReadonlyArray<T>;

Union

• @template T - A tuple or array type. *

Constructs a union type from the element types of the tuple or array T. Equivalent to T[number].

export type Union<T extends unknown[]> = T[number];

ExtractTail

• @template T - A tuple type with at least one element. *

Given a tuple T, constructs a new tuple containing all elements except the first. Returns never when T has fewer than two elements.

export type ExtractTail<T extends unknown[]> =
	T extends [unknown, ...infer Tail] ? Tail : never;

ExtractMiddle

• @template T - A tuple type with at least two elements. *

Given a tuple T, constructs a new tuple containing all elements except the first and the last. Returns never when T has fewer than three elements.

export type ExtractMiddle<T extends unknown[]> =
	T extends [unknown, ...infer Tail, unknown] ? Tail : never;

ExtractHead

• @template T - A tuple type with at least one element. *

Given a tuple T, constructs a new tuple containing all elements except the last. Returns never when T has fewer than two elements.

export type ExtractHead<T extends unknown[]> =
	T extends [...infer Tail, unknown] ? Tail : never;

PartialRecord

• @template K - The key type, constrained to valid record key types.
• @template T - The value type. *

Constructs a Record<K, T> where all properties are optional. A shorthand for Partial<Record<K, T>>.

export type PartialRecord<K extends keyof any, T> = Partial<Record<K, T>>;

ArrayMinLength1

• @template T - The element type. *

Constructs an Array<T> that is guaranteed to contain at least one element. Enforced via an intersection with { 0: T }, making index 0 always required.

export type ArrayMinLength1<T> = { 0: T } & Array<T>;

LanguageBCP47Tags

A union of all valid BCP 47 language tags supported by the library. Each tag is a combination of an ISO 639-1 language code and an ISO 3166-1 alpha-2 region code (e.g. "en-US", "it-IT", "zh-CN"). Used to type locale parameters in internationalisation utilities.

export type LanguageBCP47Tags =
	| "ar-SA" | "bn-BD" | "bn-IN" | "cs-CZ" | "da-DK"
	| "de-AT" | "de-CH" | "de-DE" | "el-GR" | "en-AU"
	| "en-CA" | "en-GB" | "en-IE" | "en-IN" | "en-NZ"
	| "en-US" | "en-ZA" | "es-AR" | "es-CL" | "es-CO"
	| "es-ES" | "Central-No" | "es-MX" | "es-US" | "fi-FI"
	| "fr-BE" | "fr-CA" | "fr-CH" | "fr-FR" | "he-IL"
	| "hi-IN" | "hu-HU" | "id-ID" | "it-CH" | "it-IT"
	| "ja-JP" | "ko-KR" | "nl-BE" | "nl-NL" | "no-NO"
	| "pl-PL" | "pt-BR" | "pt-PT" | "ro-RO" | "ru-RU"
	| "sk-SK" | "sv-SE" | "ta-IN" | "ta-LK" | "th-TH"
	| "tr-TR" | "zh-CN" | "zh-HK" | "zh-TW";

TypedArray

A union of all Typed Array constructors. Useful for constraining parameters that accept any fixed-size binary array view over an ArrayBuffer.

Includes: Int8Array, Uint8Array, Uint8ClampedArray, Int16Array, Uint16Array, Int32Array, Uint32Array, Float32Array, Float64Array, BigInt64Array, BigUint64Array.

export type TypedArray =
	| Int8Array | Uint8Array | Uint8ClampedArray
	| Int16Array | Uint16Array
	| Int32Array | Uint32Array
	| Float32Array | Float64Array
	| BigInt64Array | BigUint64Array;

KeyboardEventCode

A union of all valid KeyboardEvent.code string values. Represents the physical key on the keyboard regardless of the user's active keyboard layout or language. Used to type parameters in keyboard event utilities such as {@link useHotKeys} and {@link clickElementOnKeydownEvent}.

export type KeyboardEventCode =
	| "Escape" | "Digit1" | "Digit2" | "Digit3" | "Digit4" | "Digit5"
	| "Digit6" | "Digit7" | "Digit8" | "Digit9" | "Digit0" | "Minus"
	| "Equal" | "Backspace" | "Tab" | "KeyQ" | "KeyW" | "KeyE" | "KeyR"
	| "KeyT" | "KeyY" | "KeyU" | "KeyI" | "KeyO" | "KeyP" | "BracketLeft"
	| "BracketRight" | "Enter" | "ControlLeft" | "KeyA" | "KeyS" | "KeyD"
	| "KeyF" | "KeyG" | "KeyH" | "KeyJ" | "KeyK" | "KeyL" | "Semicolon"
	| "Quote" | "Backquote" | "ShiftLeft" | "Backslash" | "KeyZ" | "KeyX"
	| "KeyC" | "KeyV" | "KeyB" | "KeyN" | "KeyM" | "Comma" | "Period"
	| "Slash" | "ShiftRight" | "NumpadMultiply" | "AltLeft" | "Space"
	| "CapsLock" | "F1" | "F2" | "F3" | "F4" | "F5" | "F6" | "F7" | "F8"
	| "F9" | "F10" | "Pause" | "ScrollLock" | "Numpad7" | "Numpad8"
	| "Numpad9" | "NumpadSubtract" | "Numpad4" | "Numpad5" | "Numpad6"
	| "NumpadAdd" | "Numpad1" | "Numpad2" | "Numpad3" | "Numpad0"
	| "NumpadDecimal" | "IntlBackslash" | "F11" | "F12" | "NumpadEqual"
	| "F13" | "F14" | "F15" | "F16" | "F17" | "F18" | "F19" | "F20"
	| "F21" | "F22" | "F23" | "KanaMode" | "Lang2" | "Lang1" | "IntlRo"
	| "F24" | "Lang4" | "Lang3" | "Convert" | "NonConvert" | "IntlYen"
	| "NumpadComma" | "MediaTrackPrevious" | "MediaTrackNext" | "NumpadEnter"
	| "ControlRight" | "AudioVolumeMute" | "LaunchApp2" | "MediaPlayPause"
	| "MediaStop" | "VolumeDown" | "AudioVolumeDown" | "VolumeUp"
	| "AudioVolumeUp" | "BrowserHome" | "NumpadDivide" | "PrintScreen"
	| "AltRight" | "NumLock" | "Home" | "ArrowUp" | "PageUp" | "ArrowLeft"
	| "ArrowRight" | "End" | "ArrowDown" | "PageDown" | "Insert" | "Delete"
	| "MetaLeft" | "OSLeft" | "MetaRight" | "ContextMenu" | "Power"
	| "BrowserSearch" | "BrowserFavorites" | "BrowserRefresh" | "BrowserStop"
	| "BrowserForward" | "BrowserBack" | "LaunchApp1" | "LaunchMail"
	| "MediaSelect";