feat(postgrest): add stripNulls method for null value stripping (#2189)

Author: TheSeydiCharyyev

packages/core/postgrest-js/src/PostgrestBuilder.ts

@@ -83,6 +83,7 @@ export default abstract class PostgrestBuilder<
   protected signal?: AbortSignal
   protected fetch: Fetch
   protected isMaybeSingle: boolean
+  protected shouldStripNulls: boolean
   protected urlLengthLimit: number
 
   // Retry configuration - enabled by default
@@ -123,6 +124,7 @@ export default abstract class PostgrestBuilder<
     signal?: AbortSignal
     fetch?: Fetch
     isMaybeSingle?: boolean
+    shouldStripNulls?: boolean
     urlLengthLimit?: number
     // Retry option
     retry?: boolean
@@ -135,6 +137,7 @@ export default abstract class PostgrestBuilder<
     this.shouldThrowOnError = builder.shouldThrowOnError ?? false
     this.signal = builder.signal
     this.isMaybeSingle = builder.isMaybeSingle ?? false
+    this.shouldStripNulls = builder.shouldStripNulls ?? false
     this.urlLengthLimit = builder.urlLengthLimit ?? 8000
     this.retryEnabled = builder.retry ?? true
 
@@ -158,6 +161,63 @@ export default abstract class PostgrestBuilder<
     return this as this & PostgrestBuilder<ClientOptions, Result, true>
   }
 
+  /**
+   * Strip null values from the response data. Properties with `null` values
+   * will be omitted from the returned JSON objects.
+   *
+   * Requires PostgREST 11.2.0+.
+   *
+   * {@link https://docs.postgrest.org/en/stable/references/api/resource_representation.html#stripped-nulls}
+   *
+   * @category Database
+   *
+   * @example With `select()`
+   * ```ts
+   * const { data, error } = await supabase
+   *   .from('characters')
+   *   .select()
+   *   .stripNulls()
+   * ```
+   *
+   * @exampleSql With `select()`
+   * ```sql
+   * create table
+   *   characters (id int8 primary key, name text, bio text);
+   *
+   * insert into
+   *   characters (id, name, bio)
+   * values
+   *   (1, 'Luke', null),
+   *   (2, 'Leia', 'Princess of Alderaan');
+   * ```
+   *
+   * @exampleResponse With `select()`
+   * ```json
+   * {
+   *   "data": [
+   *     {
+   *       "id": 1,
+   *       "name": "Luke"
+   *     },
+   *     {
+   *       "id": 2,
+   *       "name": "Leia",
+   *       "bio": "Princess of Alderaan"
+   *     }
+   *   ],
+   *   "status": 200,
+   *   "statusText": "OK"
+   * }
+   * ```
+   */
+  stripNulls(): this {
+    if (this.headers.get('Accept') === 'text/csv') {
+      throw new Error('stripNulls() cannot be used with csv()')
+    }
+    this.shouldStripNulls = true
+    return this
+  }
+
   /**
    * Set an HTTP header for the request.
    *
@@ -222,6 +282,16 @@ export default abstract class PostgrestBuilder<
       this.headers.set('Content-Type', 'application/json')
     }
 
+    // https://docs.postgrest.org/en/stable/references/api/resource_representation.html#stripped-nulls
+    if (this.shouldStripNulls) {
+      const currentAccept = this.headers.get('Accept')
+      if (currentAccept === 'application/vnd.pgrst.object+json') {
+        this.headers.set('Accept', 'application/vnd.pgrst.object+json;nulls=stripped')
+      } else if (!currentAccept || currentAccept === 'application/json') {
+        this.headers.set('Accept', 'application/vnd.pgrst.array+json;nulls=stripped')
+      }
+    }
+
     // NOTE: Invoke w/o `this` to avoid illegal invocation error.
     // https://github.com/supabase/postgrest-js/pull/247
     const _fetch = this.fetch

packages/core/postgrest-js/test/transforms.test.ts

@@ -315,6 +315,43 @@ test('csv', async () => {
   `)
 })
 
+test('stripNulls', async () => {
+  const res = await postgrest.from('users').select().stripNulls()
+  // Null fields (data, age_range, catchphrase) should be stripped from rows where they are null
+  expect(res.error).toBeNull()
+  expect(res.status).toBe(200)
+  expect(Array.isArray(res.data)).toBe(true)
+  // Check that a row with null `data` does not have the `data` key
+  const supabot = (res.data as any[])?.find((u: any) => u.username === 'supabot')
+  expect(supabot).toBeDefined()
+  expect(supabot).not.toHaveProperty('data')
+  expect(supabot).toHaveProperty('username')
+  // Check that a row with non-null `data` still has it
+  const jsonuser = (res.data as any[])?.find((u: any) => u.username === 'jsonuser')
+  expect(jsonuser).toBeDefined()
+  expect(jsonuser).toHaveProperty('data')
+})
+
+test('stripNulls with single', async () => {
+  const res = await postgrest
+    .from('users')
+    .select()
+    .eq('username', 'supabot')
+    .limit(1)
+    .single()
+    .stripNulls()
+  expect(res.error).toBeNull()
+  expect(res.status).toBe(200)
+  expect(res.data).not.toHaveProperty('data')
+  expect((res.data as any)?.username).toBe('supabot')
+})
+
+test('stripNulls throws when used with csv', () => {
+  expect(() => postgrest.from('users').select().csv().stripNulls()).toThrow(
+    'stripNulls() cannot be used with csv()'
+  )
+})
+
 test('geojson', async () => {
   const res = await postgrest.from('shops').select().geojson()
   expect(res).toMatchInlineSnapshot(`