small fixes and tests

Author: mydea

.size-limit.js

@@ -160,7 +160,7 @@ module.exports = [
     name: 'CDN Bundle (incl. Tracing)',
     path: createCDNPath('bundle.tracing.min.js'),
     gzip: true,
-    limit: '38 KB',
+    limit: '39 KB',
   },
   {
     name: 'CDN Bundle (incl. Tracing, Replay)',

packages/core/src/utils/merge.ts

@@ -1,12 +1,14 @@
 /**
  * Shallow merge two objects.
  * Does not mutate the passed in objects.
+ * Undefined/empty values in the merge object will overwrite existing values.
+ *
  * By default, this merges 2 levels deep.
  */
 export function merge<T>(initialObj: T, mergeObj: T, levels = 2): T {
   // If the merge value is not an object, or we have no merge levels left,
   // we just set the value to the merge value
-  if (typeof mergeObj !== 'object' || levels <= 0) {
+  if (!mergeObj || typeof mergeObj !== 'object' || levels <= 0) {
     return mergeObj;
   }
 

packages/core/test/lib/utils/merge.test.ts

@@ -51,4 +51,25 @@ describe('merge', () => {
     expect(actual).not.toBe(oldData);
     expect(actual).not.toBe(newData);
   });
+
+  it.each([
+    [undefined, { a: 'aa' }, { a: 'aa' }],
+    [{ a: 'aa' }, undefined, undefined],
+    [{ a: 'aa' }, null, null],
+    [{ a: 'aa' }, { a: undefined }, { a: undefined }],
+    [{ a: 'aa' }, { a: null }, { a: null }],
+    [{ a: 'aa' }, { a: '' }, { a: '' }],
+    [
+      { a0: { a1: { a2: { a3: { a4: 'a4a' }, a3a: 'a3a' }, a2a: 'a2a' }, a1a: 'a1a' }, a0a: 'a0a' },
+      { a0: { a1: { a2: { a3: { a4: 'a4b' }, a3b: 'a3b' }, a2b: 'a2b' }, a1b: 'a1b' }, a0b: 'a0b' },
+      {
+        a0: { a1: { a2: { a3: { a4: 'a4a' }, a3b: 'a3a' }, a2b: 'a2b' }, a1b: 'a1b', a1a: 'a1a' },
+        a0b: 'a0b',
+        a0a: 'a0a',
+      },
+    ],
+  ])('works with %p and %p', (oldData, newData, expected) => {
+    const actual = merge(oldData, newData as any);
+    expect(actual).toEqual(expected);
+  });
 });