feat: allow readonly array parameters

src/app/Navigation.tsx

@@ -13,7 +13,7 @@ interface NavigationItem {
   count?: number;
 }
 
-const navigation: NavigationItem[] = [
+const navigation: readonly NavigationItem[] = [
   { name: 'Dashboard', icon: HomeIcon, href: '/' },
   { name: 'Team', icon: UsersIcon, href: '/team', count: 3 },
   { name: 'Projects', icon: FolderIcon, href: '/projects', count: 4 },
@@ -23,7 +23,7 @@ export default function Navigation() {
   const navigate = useNavigate();
   const { pathname } = useLocation();
 
-  const shortcuts: KbsDefinition[] = [
+  const shortcuts: readonly KbsDefinition[] = [
     {
       shortcut: { key: 'PageUp', shift: true },
       handler() {

src/app/useCounter.ts

@@ -7,7 +7,7 @@ export function useCounter(
 ) {
   const { allowC = true, maxFrequency } = options;
   const [counter, setCounter] = useState(0);
-  const shortcuts: KbsDefinition[] = [
+  const shortcuts: readonly KbsDefinition[] = [
     {
       shortcut: allowC ? ['i', 'c'] : ['i'],
       handler() {

src/component/hooks/use_kbs.ts

@@ -8,7 +8,7 @@ import {
   useLastTriggerRef,
 } from '../utils/get_key_down_handler.ts';
 
-export function useKbs(shortcuts: KbsDefinition[]) {
+export function useKbs(shortcuts: readonly KbsDefinition[]) {
   const lastTrigger = useLastTriggerRef();
   const combinedShortcuts = useMemo(
     () => combineShortcuts(cleanShortcuts([shortcuts])),

src/component/hooks/use_kbs_global.ts

@@ -3,7 +3,7 @@ import { useEffect } from 'react';
 import { useKbsDispatch } from '../kbs_context.ts';
 import type { KbsDefinition } from '../types.ts';
 
-export function useKbsGlobal(shortcuts: KbsDefinition[]) {
+export function useKbsGlobal(shortcuts: readonly KbsDefinition[]) {
   const kbsDispatch = useKbsDispatch();
   useEffect(() => {
     kbsDispatch({ type: 'INIT', shortcuts });

src/component/hooks/use_kbs_global_list.ts

@@ -3,7 +3,7 @@ import { useContext } from 'react';
 import { kbsContext } from '../kbs_context.ts';
 import type { KbsShortcut } from '../types.ts';
 
-export function useKbsGlobalList(): KbsShortcut[] {
+export function useKbsGlobalList(): readonly KbsShortcut[] {
   return useContext(kbsContext).cleanedShortcuts.map(
     ({ handler, ...rest }) => rest,
   );

src/component/kbs_context.ts

@@ -6,15 +6,15 @@ import { cleanShortcuts } from './utils/clean_shortcuts.ts';
 import { combineShortcuts } from './utils/combine_shortcuts.ts';
 
 interface KbsState {
-  inputShortcuts: KbsDefinition[][];
-  cleanedShortcuts: KbsInternalShortcut[];
+  inputShortcuts: ReadonlyArray<readonly KbsDefinition[]>;
+  cleanedShortcuts: readonly KbsInternalShortcut[];
   combinedShortcuts: Record<string, KbsInternalShortcut>;
   disableCount: number;
 }
 
 type KbsAction =
-  | { type: 'INIT'; shortcuts: KbsDefinition[] }
-  | { type: 'CLEANUP'; shortcuts: KbsDefinition[] }
+  | { type: 'INIT'; shortcuts: readonly KbsDefinition[] }
+  | { type: 'CLEANUP'; shortcuts: readonly KbsDefinition[] }
   | { type: 'DISABLE_GLOBAL' }
   | { type: 'ENABLE_GLOBAL' };
 

src/component/types.ts

@@ -30,7 +30,10 @@ export interface KbsDefinition {
   /**
    * The definition of key(s) that will trigger the shortcut.
    */
-  shortcut: string | KbsKeyDefinition | Array<string | KbsKeyDefinition>;
+  shortcut:
+    | string
+    | KbsKeyDefinition
+    | ReadonlyArray<string | KbsKeyDefinition>;
   /**
    * The handler function to call when the shortcut is triggered.
    */
@@ -48,7 +51,7 @@ export interface KbsDefinition {
 
 export interface KbsShortcut {
   shortcut: KbsKeyDefinition;
-  aliases: KbsKeyDefinition[];
+  aliases: readonly KbsKeyDefinition[];
   meta?: KbsMetadata;
 }
 

src/component/utils/clean_shortcuts.ts

@@ -13,8 +13,8 @@ const defaultModifiers: Modifiers = {
 };
 
 export function cleanShortcuts(
-  inputs: KbsDefinition[][],
-): KbsInternalShortcut[] {
+  inputs: ReadonlyArray<readonly KbsDefinition[]>,
+): readonly KbsInternalShortcut[] {
   const result: KbsInternalShortcut[] = [];
   for (const input of inputs) {
     for (const definition of input) {
@@ -32,11 +32,17 @@ export function cleanShortcuts(
 }
 
 function shortcutToObjects(
-  shortcut: string | KbsKeyDefinition | Array<string | KbsKeyDefinition>,
-): KbsKeyDefinition[] {
+  shortcut:
+    | string
+    | KbsKeyDefinition
+    | ReadonlyArray<string | KbsKeyDefinition>,
+): readonly KbsKeyDefinition[] {
   if (typeof shortcut === 'string') {
     return [{ ...defaultModifiers, key: shortcut.toLowerCase() }];
-  } else if (Array.isArray(shortcut)) {
+  } else if (
+    // Cannot use `Array.isArray` because it does not narrow `ReadonlyArray` (<https://github.com/microsoft/TypeScript/issues/17002>)
+    'map' in shortcut
+  ) {
     return shortcut.map((shortcut) => {
       if (typeof shortcut === 'string') {
         return { ...defaultModifiers, key: shortcut.toLowerCase() };

src/component/utils/combine_shortcuts.ts

@@ -3,7 +3,7 @@ import type { KbsInternalShortcut } from '../types.ts';
 import { shortcutToKeys } from './make_key.ts';
 
 export function combineShortcuts(
-  shortcuts: KbsInternalShortcut[],
+  shortcuts: readonly KbsInternalShortcut[],
 ): Record<string, KbsInternalShortcut> {
   const result: Record<string, KbsInternalShortcut> = {};
   for (const shortcut of shortcuts) {

src/component/utils/make_key.ts

@@ -10,7 +10,9 @@ export interface Modifiers {
   alt?: boolean;
 }
 
-export function shortcutToKeys(shortcut: KbsInternalShortcut): string[] {
+export function shortcutToKeys(
+  shortcut: KbsInternalShortcut,
+): readonly string[] {
   return [
     ...shortcutObjectToKey(shortcut.shortcut),
     ...shortcut.aliases.flatMap(shortcutObjectToKey),