fix(ui): equals filter shows no results when value is cleared (#14673)

### What?

Fixes a bug where clearing the value of an 'equals' filter in the
collection list view would show no results (or only documents with empty
string values) instead of showing all documents.

### Why?

When a user cleared a filter value using backspace or delete, the
WhereBuilder was converting the `null` value to an empty string `''`.
This caused the query to become `equals=''`, which filtered for
documents where the field equals an empty string, rather than treating
it as "no filter" and showing all documents.

This was inconsistent with the initial behavior when a filter is first
added without a value, where all documents are displayed.

### How?

Updated the `updateValue` function to pass `undefined` instead of an
empty string when the debounced value is `null` or empty:

```typescript
value: debouncedValue === null || debouncedValue === '' ? undefined : debouncedValue,
```

Fixes #14627

Author: PatrikKozak

packages/ui/src/elements/WhereBuilder/Condition/index.tsx

@@ -74,15 +74,15 @@ export const Condition: React.FC<Props> = (props) => {
     valueOptions = reducedField.field.options
   }
 
-  const updateValue = useEffectEvent(async (debouncedValue) => {
+  const updateValue = useEffectEvent(async (debouncedValue: Value) => {
     if (operator) {
       await updateCondition({
         type: 'value',
         andIndex,
         field: reducedField,
         operator,
         orIndex,
-        value: debouncedValue === null ? '' : debouncedValue,
+        value: debouncedValue === null || debouncedValue === '' ? undefined : debouncedValue,
       })
     }
   })

test/admin/e2e/list-view/e2e.spec.ts

@@ -742,6 +742,33 @@ describe('List View', () => {
       await expect(valueInput).toHaveValue('Test')
     })
 
+    test('should show all documents when equals filter value is cleared', async () => {
+      await page.goto(postsUrl.list)
+
+      await expect(page.locator(tableRowLocator)).toHaveCount(2)
+
+      const { whereBuilder } = await addListFilter({
+        page,
+        fieldLabel: 'Title',
+        operatorLabel: 'equals',
+        value: 'post1',
+      })
+
+      // Wait for filter to be applied
+      await page.waitForTimeout(500)
+
+      await expect(page.locator(tableRowLocator)).toHaveCount(1)
+
+      const valueInput = whereBuilder.locator('.condition__value >> input')
+      await valueInput.clear()
+
+      // Wait for debounce
+      await page.waitForTimeout(500)
+
+      // Should now show all 2 posts again (not 0 posts)
+      await expect(page.locator(tableRowLocator)).toHaveCount(2)
+    })
+
     test('should still show second filter if two filters exist and first filter is removed', async () => {
       await page.goto(postsUrl.list)
 

test/admin/payload-types.ts

@@ -98,6 +98,7 @@ export interface Config {
     'list-view-select-api': ListViewSelectApi;
     virtuals: Virtual;
     'no-timestamps': NoTimestamp;
+    'payload-kv': PayloadKv;
     'payload-locked-documents': PayloadLockedDocument;
     'payload-preferences': PayloadPreference;
     'payload-migrations': PayloadMigration;
@@ -135,13 +136,15 @@ export interface Config {
     'list-view-select-api': ListViewSelectApiSelect<false> | ListViewSelectApiSelect<true>;
     virtuals: VirtualsSelect<false> | VirtualsSelect<true>;
     'no-timestamps': NoTimestampsSelect<false> | NoTimestampsSelect<true>;
+    'payload-kv': PayloadKvSelect<false> | PayloadKvSelect<true>;
     'payload-locked-documents': PayloadLockedDocumentsSelect<false> | PayloadLockedDocumentsSelect<true>;
     'payload-preferences': PayloadPreferencesSelect<false> | PayloadPreferencesSelect<true>;
     'payload-migrations': PayloadMigrationsSelect<false> | PayloadMigrationsSelect<true>;
   };
   db: {
     defaultIDType: string;
   };
+  fallbackLocale: ('false' | 'none' | 'null') | false | null | ('es' | 'en') | ('es' | 'en')[];
   globals: {
     'hidden-global': HiddenGlobal;
     'not-in-view-global': NotInViewGlobal;
@@ -637,6 +640,23 @@ export interface NoTimestamp {
   id: string;
   title?: string | null;
 }
+/**
+ * This interface was referenced by `Config`'s JSON-Schema
+ * via the `definition` "payload-kv".
+ */
+export interface PayloadKv {
+  id: string;
+  key: string;
+  data:
+    | {
+        [k: string]: unknown;
+      }
+    | unknown[]
+    | string
+    | number
+    | boolean
+    | null;
+}
 /**
  * This interface was referenced by `Config`'s JSON-Schema
  * via the `definition` "payload-locked-documents".
@@ -1227,6 +1247,14 @@ export interface VirtualsSelect<T extends boolean = true> {
 export interface NoTimestampsSelect<T extends boolean = true> {
   title?: T;
 }
+/**
+ * This interface was referenced by `Config`'s JSON-Schema
+ * via the `definition` "payload-kv_select".
+ */
+export interface PayloadKvSelect<T extends boolean = true> {
+  key?: T;
+  data?: T;
+}
 /**
  * This interface was referenced by `Config`'s JSON-Schema
  * via the `definition` "payload-locked-documents_select".