fix(Object): Optional fields break FromEntries

BHC-IT · Jun 1, 2023 · 48ebe41 · 48ebe41
1 parent a68d742
commit 48ebe41
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Showing 2 changed files with 14 additions and 2 deletions.
diff --git a/tests/Oject.test.d.ts b/tests/Oject.test.d.ts
@@ -86,7 +86,13 @@ declare module '../types' {
         Expect<
           Equal<
             FromEntries<
-              [Entries<Dummy, 'aString'>, Entries<Dummy, 'aNumber'>, Entries<Dummy, 'anObject'>]
+              [
+                Entries<Dummy, 'string'>,
+                Entries<Dummy, 'number'>,
+                Entries<Dummy, 'object'>,
+                Entries<Dummy, 'optional'>,
+                Entries<Dummy, 'polymorphic'>
+              ]
             >,
             Dummy
           >

diff --git a/types/Object.d.ts b/types/Object.d.ts
@@ -30,6 +30,12 @@ export namespace Object {
     = E extends EmptyArray
       ? {}
       : E extends [infer First extends ObjectEntry, ...infer Tail extends ObjectEntry[]]
-        ? MergeInsertions<{[k in First[0]]: First[1]} & FromEntries<Tail>>
+        ? MergeInsertions<
+            & IfExtends<First[1], NonNullable<First[1]>,
+              { [k in First[0]]: First[1] },
+              { [k in First[0]]?: First[1] }
+            >
+            & FromEntries<Tail>
+          >
         : never
 }