fix: add missing readonlyness

RebeccaStevens · Sep 13, 2021 · 32bc77a · 32bc77a
1 parent da9774e
commit 32bc77a
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Showing 3 changed files with 24 additions and 22 deletions.
diff --git a/src/deepmerge.ts b/src/deepmerge.ts
@@ -130,7 +130,7 @@ function mergeUnknowns<
 
     if (type === ObjectType.ARRAY) {
       return utils.mergeFunctions.mergeArrays(
-        values as ReadonlyArray<unknown[]>,
+        values as ReadonlyArray<ReadonlyArray<unknown>>,
         utils
       ) as DeepMergeHKT<Ts, MF>;
     }
@@ -194,7 +194,7 @@ function mergeRecords<
  * @param values - The arrays.
  */
 function mergeArrays<
-  Ts extends ReadonlyArray<unknown[]>,
+  Ts extends ReadonlyArray<ReadonlyArray<unknown>>,
   U extends DeepMergeMergeFunctionUtils,
   MF extends DeepMergeMergeFunctionsURIs
 >(values: Ts, utils: U) {

diff --git a/src/types/merging.ts b/src/types/merging.ts
@@ -153,14 +153,15 @@ export type DeepMergeLeafHKT<
 /**
  * Get the leaf type from many types that can't be merged.
  */
-export type DeepMergeLeaf<Ts extends ReadonlyArray<unknown>> = Ts extends []
-  ? never
-  : Ts extends [infer T]
-  ? T
-  : Ts extends [...infer Rest, infer Tail]
-  ? IsNever<Tail> extends true
-    ? Rest extends ReadonlyArray<unknown>
-      ? DeepMergeLeaf<Rest>
-      : never
-    : Tail
-  : never;
+export type DeepMergeLeaf<Ts extends ReadonlyArray<unknown>> =
+  Ts extends readonly []
+    ? never
+    : Ts extends [infer T]
+    ? T
+    : Ts extends [...infer Rest, infer Tail]
+    ? IsNever<Tail> extends true
+      ? Rest extends ReadonlyArray<unknown>
+        ? DeepMergeLeaf<Rest>
+        : never
+      : Tail
+    : never;
diff --git a/src/types/utils.ts b/src/types/utils.ts
@@ -172,7 +172,7 @@ export type UnionSetValues<Ts extends ReadonlyArray<unknown>> =
 export type UnionMapKeys<Ts extends ReadonlyArray<unknown>> =
   Ts extends readonly [infer Head, ...infer Rest]
     ? Head extends Map<infer K1, unknown>
-      ? Rest extends []
+      ? Rest extends readonly []
         ? K1
         : K1 | UnionMapKeys<Rest>
       : never
@@ -184,7 +184,7 @@ export type UnionMapKeys<Ts extends ReadonlyArray<unknown>> =
 export type UnionMapValues<Ts extends ReadonlyArray<unknown>> =
   Ts extends readonly [infer Head, ...infer Rest]
     ? Head extends Map<unknown, infer V1>
-      ? Rest extends []
+      ? Rest extends readonly []
         ? V1
         : UnionMapValues<Rest> | V1
       : never
@@ -251,13 +251,14 @@ export type OptionalKeysOf<Ts extends readonly [unknown, ...unknown[]]> =
 /**
  * Filter out nevers from a tuple.
  */
-export type FilterOutNever<T extends ReadonlyArray<unknown>> = T extends []
-  ? []
-  : T extends [infer Head, ...infer Rest]
-  ? IsNever<Head> extends true
-    ? FilterOutNever<Rest>
-    : [Head, ...FilterOutNever<Rest>]
-  : T;
+export type FilterOutNever<T extends ReadonlyArray<unknown>> =
+  T extends readonly []
+    ? []
+    : T extends [infer Head, ...infer Rest]
+    ? IsNever<Head> extends true
+      ? FilterOutNever<Rest>
+      : [Head, ...FilterOutNever<Rest>]
+    : T;
 
 /**
  * Is the type a tuple?