Map entries with filtering

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+  "autoHide.autoHidePanel": false
+}

cdn/radash.esm.js

@@ -636,8 +636,9 @@ const mapEntries = (obj, toEntry) => {
   if (!obj)
     return {};
   return Object.entries(obj).reduce((acc, [key, value]) => {
-    const [newKey, newValue] = toEntry(key, value);
-    acc[newKey] = newValue;
+    const alteredEntry = toEntry(key, value);
+    if (alteredEntry !== void 0)
+      acc[alteredEntry[0]] = alteredEntry[1];
     return acc;
   }, {});
 };

cdn/radash.js

@@ -639,8 +639,9 @@ var radash = (function (exports) {
     if (!obj)
       return {};
     return Object.entries(obj).reduce((acc, [key, value]) => {
-      const [newKey, newValue] = toEntry(key, value);
-      acc[newKey] = newValue;
+      const alteredEntry = toEntry(key, value);
+      if (alteredEntry !== void 0)
+        acc[alteredEntry[0]] = alteredEntry[1];
       return acc;
     }, {});
   };

docs/object/map-entries.mdx

@@ -9,7 +9,8 @@ group: Object
 Iterates the entries of an object, calling the given `toEntry` callback function
 to generate new entries. It's a `_.mapValues` and `_.mapKeys`
 in one. The `toEntry` callback function should return an array with
-two items `[key, value]` (a.k.a the new entry).
+two items `[key, value]` (a.k.a the new entry).  If the function returns 
+`undefined`, the entry will be ignored
 
 ```ts
 import { mapEntries } from 'radash'
@@ -21,5 +22,6 @@ const ra = {
   culture: 'egypt'
 }
 
-mapEntries(ra, (key, value) => [key.toUpperCase(), `${value}`]) // => { NAME: 'Ra', POWER: 'sun', RANK: '100', CULTURE: 'egypt' }
+mapEntries(ra, (key, value) => key === 'culture' ? undefined : [key.toUpperCase(), `${value}`]) 
+// => { NAME: 'Ra', POWER: 'sun', RANK: '100' }
 ```

src/object.ts

@@ -78,12 +78,12 @@ export const mapEntries = <
   TNewValue
 >(
   obj: Record<TKey, TValue>,
-  toEntry: (key: TKey, value: TValue) => [TNewKey, TNewValue]
+  toEntry: (key: TKey, value: TValue) => [TNewKey, TNewValue] | undefined
 ): Record<TNewKey, TNewValue> => {
   if (!obj) return {} as Record<TNewKey, TNewValue>
   return Object.entries(obj).reduce((acc, [key, value]) => {
-    const [newKey, newValue] = toEntry(key as TKey, value as TValue)
-    acc[newKey] = newValue
+    const alteredEntry = toEntry(key as TKey, value as TValue)
+    if (alteredEntry !== undefined) acc[alteredEntry[0]] = alteredEntry[1]
     return acc
   }, {} as Record<TNewKey, TNewValue>)
 }

src/tests/object.test.ts

@@ -376,6 +376,15 @@ describe('object module', () => {
       assert.equal(result.fey, 'USER')
       assert.equal(result.bray, 'GUEST')
     })
+    test('filtering', () => {
+      const result = _.mapEntries(peopleByRole, (key, value) =>
+        key === 'guest' ? undefined : [value, key.toUpperCase()]
+      )
+      assert.equal(Object.keys(result).length, 2)
+      assert.equal(result.jay, 'ADMIN')
+      assert.equal(result.fey, 'USER')
+      assert.equal(result.bray, undefined)
+    })
   })
 
   describe('invert function', () => {