feat: Serialize null

BREAKING CHANGE: The primitive value null will now be serialized instead
of removed, e.g., { foo: null } will now be serialized to 'foo='.

Author: razor-x

README.md

@@ -29,8 +29,10 @@ the consumer parsing the string, it can be unambigously parsed back to the origi
 - The primitive `number` and `bigint` types are serialized using `.toString()`.
 - The primitive `boolean` type is serialized using `.toString()`,
   e.g., `{ foo: true, bar: false }` serializes to `foo=true&bar=false`.
-- The primitive `null` and `undefined` values are removed,
-  e.g., `{ foo: null, bar: undefined, baz: 1 }` serializes to `baz=1`.
+- The primitive `null` is serialized to an empty value,
+  e.g., `{ foo: null }` serializes to `foo=`.
+- and `undefined` values are removed,
+  e.g., `{ foo: undefined, bar: 1 }` serializes to `baz=1`.
 - `Date` objects are detected and serialized using `Date.toISOString()`,
   e.g., `{ foo: new Date(0) }` serializes to `foo=1970-01-01T00%3A00%3A00.000Z`.
 - `Temporal.Instant` objects are detected and serialized by first converting them to `Date`

src/lib/serialize.ts

@@ -31,7 +31,10 @@ const nestedUpdateUrlSearchParams = (
 
     const name = currentPath.join('.')
 
-    if (value == null) continue
+    if (value == null) {
+      if (value === null) searchParams.set(name, '')
+      continue
+    }
 
     if (Array.isArray(value)) {
       if (value.length === 0) searchParams.set(name, '')

test/serialization.test.ts

@@ -32,9 +32,9 @@ test('removes undefined params', (t) => {
   t.is(serializeUrlSearchParams({ foo: 1, bar: undefined }), 'foo=1')
 })
 
-test('removes null params', (t) => {
-  t.is(serializeUrlSearchParams({ bar: null }), '')
-  t.is(serializeUrlSearchParams({ foo: 1, bar: null }), 'foo=1')
+test('serializes null params', (t) => {
+  t.is(serializeUrlSearchParams({ bar: null }), 'bar=')
+  t.is(serializeUrlSearchParams({ foo: 1, bar: null }), 'bar=&foo=1')
 })
 
 test('serializes empty array params', (t) => {
@@ -116,7 +116,7 @@ test('serializes plain objects', (t) => {
       foo: 1,
       bar: { baz: { x: { z: null } } },
     }),
-    'foo=1',
+    'bar.baz.x.z=&foo=1',
   )
 
   t.is(