types: type safer implementation and more accurate inference of return value type for shake

cdn/radash.esm.js

@@ -620,12 +620,10 @@ const shake = (obj, filter = (x) => x === void 0) => {
     return {};
   const keys2 = Object.keys(obj);
   return keys2.reduce((acc, key) => {
-    if (filter(obj[key])) {
-      return acc;
-    } else {
+    if (!filter(obj[key])) {
       acc[key] = obj[key];
-      return acc;
     }
+    return acc;
   }, {});
 };
 const mapKeys = (obj, mapFunc) => {

cdn/radash.js

@@ -623,12 +623,10 @@ var radash = (function (exports) {
       return {};
     const keys2 = Object.keys(obj);
     return keys2.reduce((acc, key) => {
-      if (filter(obj[key])) {
-        return acc;
-      } else {
+      if (!filter(obj[key])) {
         acc[key] = obj[key];
-        return acc;
       }
+      return acc;
     }, {});
   };
   const mapKeys = (obj, mapFunc) => {

src/object.ts

@@ -11,23 +11,30 @@ type UppercasedKeys<T extends Record<string, any>> = {
 }
 
 /**
- * Removes (shakes out) undefined entries from an
- * object. Optional second argument shakes out values
+ * Removes (shakes out) undefined entries from an object.
+ * Optional second argument shakes out values
  * by custom evaluation.
+ *
+ * @example use generics
+ * let obj = {a: 1, b: 2};
+ * shake<typeof obj, 'a'>(obj, (item) => item < 2);
+ * // -->  { b: 2 }
+ *
+ * @example default using
+ * shake({a: 1, b: 2, c: undefined})
+ * // -->  {a: 1, b: 2}
  */
-export const shake = <RemovedKeys extends string, T>(
+export const shake = <T extends Object, RemovedKeys extends keyof T>(
   obj: T,
-  filter: (value: any) => boolean = x => x === undefined
+  filter: (value: T[keyof T]) => boolean = x => x === undefined
 ): Omit<T, RemovedKeys> => {
   if (!obj) return {} as T
   const keys = Object.keys(obj) as (keyof T)[]
   return keys.reduce((acc, key) => {
-    if (filter(obj[key])) {
-      return acc
-    } else {
+    if (!filter(obj[key])) {
       acc[key] = obj[key]
-      return acc
     }
+    return acc
   }, {} as T)
 }
 

src/tests/object.test.ts

@@ -36,7 +36,7 @@ describe('object module', () => {
       })
     })
     test('handles undefined input', () => {
-      const result = _.shake(undefined)
+      const result = _.shake(undefined as unknown as Object)
       assert.deepEqual(result, {})
     })
   })