perf: an early esapes to tests when merging unknown types

src/deepmerge.ts

@@ -117,43 +117,55 @@ function mergeUnknowns<
   U extends DeepMergeMergeFunctionUtils,
   MF extends DeepMergeMergeFunctionsURIs
 >(values: Ts, utils: U): DeepMergeHKT<Ts, MF> {
-  const types = values.map(getObjectType);
-  const type = types[0];
+  const type = getObjectType(values[0]);
 
-  if (types.every((value) => value === type)) {
-    if (type === ObjectType.RECORD) {
+  // eslint-disable-next-line functional/no-conditional-statement -- add an early escape for better performance.
+  if (type !== ObjectType.NOT && type !== ObjectType.OTHER) {
+    // eslint-disable-next-line functional/no-loop-statement, functional/no-let -- using a loop here is more performant than mapping every value and then testing every value.
+    for (let i = 1; i < values.length; i++) {
+      // eslint-disable-next-line functional/no-conditional-statement -- waiting on https://github.com/jonaskello/eslint-plugin-functional/issues/269
+      if (getObjectType(values[i]) === type) {
+        continue;
+      }
+
+      return utils.mergeFunctions.mergeOthers(values, utils) as DeepMergeHKT<
+        Ts,
+        MF
+      >;
+    }
+  }
+
+  switch (type) {
+    case ObjectType.RECORD:
       return utils.mergeFunctions.mergeRecords(
         values as ReadonlyArray<Readonly<Record<RecordProperty, unknown>>>,
         utils
       ) as DeepMergeHKT<Ts, MF>;
-    }
 
-    if (type === ObjectType.ARRAY) {
+    case ObjectType.ARRAY:
       return utils.mergeFunctions.mergeArrays(
         values as ReadonlyArray<ReadonlyArray<unknown>>,
         utils
       ) as DeepMergeHKT<Ts, MF>;
-    }
 
-    if (type === ObjectType.SET) {
+    case ObjectType.SET:
       return utils.mergeFunctions.mergeSets(
         values as ReadonlyArray<Readonly<ReadonlySet<unknown>>>,
         utils
       ) as DeepMergeHKT<Ts, MF>;
-    }
 
-    if (type === ObjectType.MAP) {
+    case ObjectType.MAP:
       return utils.mergeFunctions.mergeMaps(
         values as ReadonlyArray<Readonly<ReadonlyMap<unknown, unknown>>>,
         utils
       ) as DeepMergeHKT<Ts, MF>;
-    }
-  }
 
-  return utils.mergeFunctions.mergeOthers(values, utils) as DeepMergeHKT<
-    Ts,
-    MF
-  >;
+    default:
+      return utils.mergeFunctions.mergeOthers(values, utils) as DeepMergeHKT<
+        Ts,
+        MF
+      >;
+  }
 }
 
 /**