Merge pull request #30381 from Microsoft/mapConstructor

Fix map constructor to accept readonly tuple

Author: sheetalkamat

src/lib/es2015.collection.d.ts

@@ -10,7 +10,7 @@ interface Map<K, V> {
 
 interface MapConstructor {
     new(): Map<any, any>;
-    new<K, V>(entries?: ReadonlyArray<[K, V]> | null): Map<K, V>;
+    new<K, V>(entries?: ReadonlyArray<readonly [K, V]> | null): Map<K, V>;
     readonly prototype: Map<any, any>;
 }
 declare var Map: MapConstructor;

src/lib/es2015.iterable.d.ts

@@ -129,7 +129,7 @@ interface ReadonlyMap<K, V> {
 }
 
 interface MapConstructor {
-    new <K, V>(iterable: Iterable<[K, V]>): Map<K, V>;
+    new <K, V>(iterable: Iterable<readonly [K, V]>): Map<K, V>;
 }
 
 interface WeakMap<K extends object, V> { }

tests/baselines/reference/mapConstructorOnReadonlyTuple.js

@@ -0,0 +1,7 @@
+//// [mapConstructorOnReadonlyTuple.ts]
+const pairs = [['1', 1], ['2', 2]] as const
+new Map(pairs);
+
+//// [mapConstructorOnReadonlyTuple.js]
+const pairs = [['1', 1], ['2', 2]];
+new Map(pairs);

tests/baselines/reference/mapConstructorOnReadonlyTuple.symbols

@@ -0,0 +1,8 @@
+=== tests/cases/compiler/mapConstructorOnReadonlyTuple.ts ===
+const pairs = [['1', 1], ['2', 2]] as const
+>pairs : Symbol(pairs, Decl(mapConstructorOnReadonlyTuple.ts, 0, 5))
+
+new Map(pairs);
+>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, --, --))
+>pairs : Symbol(pairs, Decl(mapConstructorOnReadonlyTuple.ts, 0, 5))
+

tests/baselines/reference/mapConstructorOnReadonlyTuple.types

@@ -0,0 +1,17 @@
+=== tests/cases/compiler/mapConstructorOnReadonlyTuple.ts ===
+const pairs = [['1', 1], ['2', 2]] as const
+>pairs : readonly [readonly ["1", 1], readonly ["2", 2]]
+>[['1', 1], ['2', 2]] as const : readonly [readonly ["1", 1], readonly ["2", 2]]
+>[['1', 1], ['2', 2]] : readonly [readonly ["1", 1], readonly ["2", 2]]
+>['1', 1] : readonly ["1", 1]
+>'1' : "1"
+>1 : 1
+>['2', 2] : readonly ["2", 2]
+>'2' : "2"
+>2 : 2
+
+new Map(pairs);
+>new Map(pairs) : Map<"1" | "2", 1 | 2>
+>Map : MapConstructor
+>pairs : readonly [readonly ["1", 1], readonly ["2", 2]]
+

tests/cases/compiler/mapConstructorOnReadonlyTuple.ts

@@ -0,0 +1,4 @@
+// @target: es2015
+
+const pairs = [['1', 1], ['2', 2]] as const
+new Map(pairs);