feat: add ReadonlyMultiKeyMap type

giladgd · Sep 14, 2024 · 7c072ef · 7c072ef
1 parent adbb9e3
commit 7c072ef
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Showing 2 changed files with 10 additions and 6 deletions.
diff --git a/src/MultiKeyMap.ts b/src/MultiKeyMap.ts
@@ -5,7 +5,7 @@ const valueSymbol = Symbol();
  */
 export class MultiKeyMap<const Key extends readonly any[], const V> {
     /** @internal */ public readonly _map: InternalMap<Key> = new Map();
-    /** @internal */ public readonly _keys = new Map<Key, V>();
+    /** @internal */ private readonly _keys = new Map<Key, V>();
 
     public constructor(entries?: readonly (readonly [key: Key, value: V])[] | MultiKeyMap<Key, V> | null) {
         if (entries != null) {
@@ -19,7 +19,7 @@ export class MultiKeyMap<const Key extends readonly any[], const V> {
      *
      * Time complexity: O(1), given that the length of the key is constant.
      */
-    public set(key: Key, value: V): this {
+    public set(key: Readonly<Key>, value: V): this {
         let map: InternalMap<Key> = this._map;
 
         for (let i = 0; i < key.length; i++) {
@@ -48,7 +48,7 @@ export class MultiKeyMap<const Key extends readonly any[], const V> {
      *
      * Time complexity: O(1), given that the length of the key is constant.
      */
-    public get(key: Key): V | undefined {
+    public get(key: Readonly<Key>): V | undefined {
         let map: InternalMap<Key> | undefined = this._map;
 
         for (let i = 0; i < key.length && map != null; i++)
@@ -69,7 +69,7 @@ export class MultiKeyMap<const Key extends readonly any[], const V> {
      *
      * Time complexity: O(1), given that the length of the key is constant.
      */
-    public has(key: Key): boolean {
+    public has(key: Readonly<Key>): boolean {
         let map: InternalMap<Key> | undefined = this._map;
 
         for (let i = 0; i < key.length && map != null; i++) {
@@ -84,7 +84,7 @@ export class MultiKeyMap<const Key extends readonly any[], const V> {
      *
      * Time complexity: O(1), given that the length of the key is constant.
      */
-    public delete(key: Key): boolean {
+    public delete(key: Readonly<Key>): boolean {
         let map: InternalMap<Key> | undefined = this._map;
         const stack: [accessMap: InternalMap<Key>, accessKey: Key[number]][] = [];
 
@@ -172,4 +172,6 @@ export class MultiKeyMap<const Key extends readonly any[], const V> {
     }
 }
 
+export type ReadonlyMultiKeyMap<Key extends readonly any[], V> = Omit<MultiKeyMap<Key, V>, "set" | "delete" | "clear">;
+
 type InternalMap<Key extends readonly any[]> = Map<Key, InternalMap<Key>> & Map<typeof valueSymbol, Key>;
diff --git a/test/MultiKeyMap.test.ts b/test/MultiKeyMap.test.ts
@@ -10,7 +10,9 @@ describe("MultiKeyMap", () => {
         map.set(["rootA", "null"], null);
         map.set(["rootB", "undefined"], undefined);
         map.set(["rootA", "num"], 4);
-        map.set(["rootA", "num2"], 8);
+
+        const key1 = ["rootA", "num2"] as const;
+        map.set(key1, 8);
 
         const map2 = new MultiKeyMap(map);