Add proposal-upsert methods to lib.esnext.collection

src/compiler/utilities.ts

@@ -1581,6 +1581,10 @@ export const getScriptTargetFeatures: () => ScriptTargetFeatures = /* @__PURE__
                 "keys",
                 "values",
             ],
+            esnext: [
+                "getOrInsert",
+                "getOrInsertComputed",
+            ],
         })),
         MapConstructor: new Map(Object.entries({
             es2024: [
@@ -1635,6 +1639,10 @@ export const getScriptTargetFeatures: () => ScriptTargetFeatures = /* @__PURE__
                 "keys",
                 "values",
             ],
+            esnext: [
+                "getOrInsert",
+                "getOrInsertComputed",
+            ],
         })),
         WeakSet: new Map(Object.entries({
             es2015: [

src/lib/esnext.collection.d.ts

@@ -1,5 +1,35 @@
 /// <reference lib="es2024.collection" />
 
+interface Map<K, V> {
+    /**
+     * Returns a specified element from the Map object.
+     * If no element is associated with the specified key, a new element with the value `defaultValue` will be inserted into the Map and returned.
+     * @returns The element associated with the specified key, which will be `defaultValue` if no element previously existed.
+     */
+    getOrInsert(key: K, defaultValue: V): V;
+    /**
+     * Returns a specified element from the Map object.
+     * If no element is associated with the specified key, the result of passing the specified key to the `callback` function will be inserted into the Map and returned.
+     * @returns The element associated with the specific key, which will be the newly computed value if no element previously existed.
+     */
+    getOrInsertComputed(key: K, callback: (key: K) => V): V;
+}
+
+interface WeakMap<K extends WeakKey, V> {
+    /**
+     * Returns a specified element from the WeakMap object.
+     * If no element is associated with the specified key, a new element with the value `defaultValue` will be inserted into the WeakMap and returned.
+     * @returns The element associated with the specified key, which will be `defaultValue` if no element previously existed.
+     */
+    getOrInsert(key: K, defaultValue: V): V;
+    /**
+     * Returns a specified element from the WeakMap object.
+     * If no element is associated with the specified key, the result of passing the specified key to the `callback` function will be inserted into the WeakMap and returned.
+     * @returns The element associated with the specific key, which will be the newly computed value if no element previously existed.
+     */
+    getOrInsertComputed(key: K, callback: (key: K) => V): V;
+}
+
 interface ReadonlySetLike<T> {
     /**
      * Despite its name, returns an iterator of the values in the set-like.

tests/baselines/reference/acceptSymbolAsWeakType.symbols

@@ -30,7 +30,7 @@ ws.delete(s);
 
 const wm = new WeakMap([[s, false]]);
 >wm : Symbol(wm, Decl(acceptSymbolAsWeakType.ts, 7, 5))
->WeakMap : Symbol(WeakMap, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>WeakMap : Symbol(WeakMap, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.esnext.collection.d.ts, --, --))
 >s : Symbol(s, Decl(acceptSymbolAsWeakType.ts, 0, 5))
 
 wm.set(s, true);

tests/baselines/reference/awaitUsingDeclarationsWithIteratorObject.symbols

@@ -55,7 +55,7 @@ async function f() {
     await using it5 = new Map<string, string>().entries();
 >it5 : Symbol(it5, Decl(awaitUsingDeclarationsWithIteratorObject.ts, 15, 15))
 >new Map<string, string>().entries : Symbol(Map.entries, Decl(lib.es2015.iterable.d.ts, --, --))
->Map : Symbol(Map, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Map : Symbol(Map, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.esnext.collection.d.ts, --, --))
 >entries : Symbol(Map.entries, Decl(lib.es2015.iterable.d.ts, --, --))
 
     await using it6 = new Set<string>().keys();

tests/baselines/reference/builtinIteratorReturn(strictbuiltiniteratorreturn=false).symbols

@@ -6,7 +6,7 @@ declare const array: number[];
 
 declare const map: Map<string, number>;
 >map : Symbol(map, Decl(builtinIteratorReturn.ts, 1, 13))
->Map : Symbol(Map, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Map : Symbol(Map, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.esnext.collection.d.ts, --, --))
 
 declare const set: Set<number>;
 >set : Symbol(set, Decl(builtinIteratorReturn.ts, 2, 13))

tests/baselines/reference/builtinIteratorReturn(strictbuiltiniteratorreturn=true).symbols

@@ -6,7 +6,7 @@ declare const array: number[];
 
 declare const map: Map<string, number>;
 >map : Symbol(map, Decl(builtinIteratorReturn.ts, 1, 13))
->Map : Symbol(Map, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Map : Symbol(Map, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.esnext.collection.d.ts, --, --))
 
 declare const set: Set<number>;
 >set : Symbol(set, Decl(builtinIteratorReturn.ts, 2, 13))

tests/baselines/reference/esNextWeakRefs_IterableWeakMap.js

@@ -50,6 +50,23 @@ export class IterableWeakMap<K extends object, V> implements WeakMap<K, V> {
         return this.#weakMap.get(key)?.value;
     }
 
+    getOrInsert(key: K, defaultValue: V): V {
+        if (!this.has(key)) {
+            this.set(key, defaultValue);
+            return defaultValue;
+        }
+        return this.get(key)!;
+    }
+
+    getOrInsertComputed(key: K, callback: (key: K) => V): V {
+        if (!this.has(key)) {
+            const value = callback(key);
+            this.set(key, value);
+            return value;
+        }
+        return this.get(key)!;
+    }
+
     delete(key: K): boolean {
         const entry = this.#weakMap.get(key);
         if (entry === undefined) {
@@ -144,6 +161,21 @@ export class IterableWeakMap {
     get(key) {
         return this.#weakMap.get(key)?.value;
     }
+    getOrInsert(key, defaultValue) {
+        if (!this.has(key)) {
+            this.set(key, defaultValue);
+            return defaultValue;
+        }
+        return this.get(key);
+    }
+    getOrInsertComputed(key, callback) {
+        if (!this.has(key)) {
+            const value = callback(key);
+            this.set(key, value);
+            return value;
+        }
+        return this.get(key);
+    }
     delete(key) {
         const entry = this.#weakMap.get(key);
         if (entry === undefined) {