Bind hasOwnProperty once

borderless · Feb 12, 2021 · b90e7c6 · b90e7c6
1 parent 562c64e
commit b90e7c6
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/src/index.ts b/src/index.ts
@@ -9,6 +9,11 @@ export type DeepPartial<T> = {
     : T[K];
 };
 
+/**
+ * Make `Object.prototype.hasOwnProperty` a reusable utility function.
+ */
+const hasOwnProperty = Function.call.bind(Object.prototype.hasOwnProperty);
+
 /**
  * Check if `value` is a simple object.
  */
@@ -46,7 +51,7 @@ export function assign<T>(target: T, value: DeepPartial<T>) {
   } else if (isObject(value)) {
     if (isObject(target)) {
       for (const key of Object.keys(value)) {
-        if (Object.prototype.hasOwnProperty.call(target, key)) {
+        if (hasOwnProperty(target, key)) {
           (target as any)[key] = assign(
             (target as any)[key],
             (value as any)[key]