fix: filter recursively

src/DeepCompositeSymbol.ts

@@ -6,19 +6,17 @@ import { isObject } from './helpers';
  * an object's entries (key-value pairs).
  */
 // tslint:disable-next-line: variable-name
-const DeepCompositeSymbol = ((object: any, keyFilter?: (key: string) => boolean) => {
-  const entries = keyFilter
-    ? Object.entries(object).filter(entry => keyFilter(entry[0]))
-    : Object.entries(object);
+const DeepCompositeSymbol = ((object: any, filter?: (entry: [string, any]) => boolean) => {
+  const entries = filter ? Object.entries(object).filter(filter) : Object.entries(object);
   // Recursively replace non-tuple object values with tuples
-  entries.forEach(update);
+  entries.forEach(x => update(x, filter));
   return Tuple.unsafeSymbol(...flatten(entries));
 }) as any;
 
-const update = (entry: any) => {
+const update = (entry: any, filter?: any) => {
   const v = entry[1];
   if (isObject(v) && !(v instanceof Tuple)) {
-    entry[1] = DeepCompositeSymbol(v);
+    entry[1] = DeepCompositeSymbol(v, filter);
   }
 };
 

test/DeepCompositeSymbol.test.ts

@@ -22,7 +22,15 @@ describe(DeepCompositeSymbol.name, () => {
   it('allows filtering by key', () => {
     const o1 = { a: { c: 1 }, b: 2, _d: 3 };
     const o2 = { ...o1, _d: 4 };
-    const filter = (key: string) => !key.startsWith('_');
+    const filter = ([key]: [string, any]) => !key.startsWith('_');
+    expect(DeepCompositeSymbol(o1, filter)).toBe(DeepCompositeSymbol(o2, filter));
+    expect(DeepCompositeSymbol(o1)).not.toBe(DeepCompositeSymbol(o2));
+  });
+
+  it('allows filtering by key recursively', () => {
+    const o1 = { a: { c: 1 }, b: 2, _d: 3 };
+    const o2 = { ...o1, a: { ...o1.a, _e: 4 } };
+    const filter = ([key]: [string, any]) => !key.startsWith('_');
     expect(DeepCompositeSymbol(o1, filter)).toBe(DeepCompositeSymbol(o2, filter));
     expect(DeepCompositeSymbol(o1)).not.toBe(DeepCompositeSymbol(o2));
   });