fix(type): union expansions in intersections

ref #556
deepkit · Mar 12, 2024 · 332b26e · 332b26e
1 parent c2a413a
commit 332b26e
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diff --git a/packages/type/src/reflection/processor.ts b/packages/type/src/reflection/processor.ts
@@ -1339,6 +1339,9 @@ export class Processor {
         }
 
         function handleUnion(a: Type, unionType: TypeUnion): Type {
+            if (a.kind === ReflectionKind.objectLiteral || a.kind === ReflectionKind.class) {
+                return unboxUnion({ kind: ReflectionKind.union, types: unionType.types.map(v => collapse(v, a)).filter(v => v.kind !== ReflectionKind.never) });
+            }
             return unboxUnion({ kind: ReflectionKind.union, types: unionType.types.filter(v => isExtendable(v, a)) });
         }
 

diff --git a/packages/type/tests/type.spec.ts b/packages/type/tests/type.spec.ts
@@ -1206,6 +1206,18 @@ test('union and intersection filters', () => {
     expect(stringifyResolvedType(typeOf<{ a: string } & { b: number }>())).toBe(`{\n  a: string;\n  b: number;\n}`);
 });
 
+test('union expansion intersection', () => {
+    type U = { a: string } | { b: number };
+    type I = U & { c: boolean };
+    expect(stringifyResolvedType(typeOf<I>())).toBe(`{
+    a: string;
+    c: boolean;
+  } | {
+    b: number;
+    c: boolean;
+  }`);
+});
+
 test('index access on any', () => {
     {
         type Map2<T> = { [K in keyof T]: T[K] };