Add distributive condition to Assign util

stitchesjs · Oct 1, 2021 · 54bf0c8 · 54bf0c8
1 parent b206022
commit 54bf0c8
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Showing 2 changed files with 17 additions and 1 deletion.
diff --git a/packages/react/tests/types.test.tsx b/packages/react/tests/types.test.tsx
@@ -166,3 +166,19 @@ void function Test() {
 		}} />
 	)
 }
+
+/* -------------------------------------------------------------------------------------------------
+ * Issue #821
+ * -----------------------------------------------------------------------------------------------*/
+
+type UnionProps = { type: 'single', collapsible: boolean; } | { type: 'multiple' };
+const UnionComponent: React.FC<UnionProps> = () => null
+const StyledUnionComponent = styled(UnionComponent, {})
+
+void function Test() {
+	<>
+		<StyledUnionComponent type="single" collapsible />
+		{/* @ts-expect-error */}
+		<StyledUnionComponent type="multiple" collapsible />
+	</>
+}
diff --git a/packages/react/types/util.d.ts b/packages/react/types/util.d.ts
@@ -5,7 +5,7 @@
 export type Prefixed<K extends string, T> = `${K}${Extract<T, boolean | number | string>}`
 
 /** Returns an object from the given object assigned with the values of another given object. */
-export type Assign<T1 = {}, T2 = {}> = Omit<T1, keyof T2> & T2
+export type Assign<T1 = {}, T2 = {}> = T1 extends any ? Omit<T1, keyof T2> & T2 : never
 
 /** Returns a widened value from the given value. */
 export type Widen<T> =