From 3cacb80c9b5fa3aa71c9d24d43cbcc10c89c8a32 Mon Sep 17 00:00:00 2001
From: Benjamin Tan <benjamin@dev.ofcr.se>
Date: Thu, 8 Feb 2024 20:19:59 +0800
Subject: [PATCH] Add support for `...` spread operator

---
 src/select-query-parser.ts | 19 +++++++++++++++++++
 test/index.test-d.ts       | 26 ++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/src/select-query-parser.ts b/src/select-query-parser.ts
index 114d59d5..e44e1e44 100644
--- a/src/select-query-parser.ts
+++ b/src/select-query-parser.ts
@@ -191,6 +191,17 @@ type ConstructFieldDefinition<
   Field
 > = Field extends { star: true }
   ? Row
+  : Field extends { spread: true; original: string; children: unknown[] }
+  ? GetResultHelper<
+      Schema,
+      (Schema['Tables'] & Schema['Views'])[Field['original']]['Row'],
+      Field['original'],
+      (Schema['Tables'] & Schema['Views'])[Field['original']] extends { Relationships: infer R }
+        ? R
+        : unknown,
+      Field['children'],
+      unknown
+    >
   : Field extends { name: string; original: string; hint: string; children: unknown[] }
   ? {
       [_ in Field['name']]: GetResultHelper<
@@ -394,12 +405,20 @@ type ParseField<Input extends string> = Input extends ''
  * - `*`
  * - a field, as defined above
  * - a renamed field, `renamed_field:field`
+ * - a spread field, `...field`
  */
 type ParseNode<Input extends string> = Input extends ''
   ? ParserError<'Empty string'>
   : // `*`
   Input extends `*${infer Remainder}`
   ? [{ star: true }, EatWhitespace<Remainder>]
+  : // `...field`
+  Input extends `...${infer Remainder}`
+  ? ParseField<EatWhitespace<Remainder>> extends [infer Field, `${infer Remainder}`]
+    ? Field extends { children: unknown[] }
+      ? [Prettify<{ spread: true } & Field>, EatWhitespace<Remainder>]
+      : ParserError<'Unable to parse spread resource'>
+    : ParserError<'Unable to parse spread resource'>
   : ParseIdentifier<Input> extends [infer Name, `${infer Remainder}`]
   ? EatWhitespace<Remainder> extends `::${infer _Remainder}`
     ? // `field::`
diff --git a/test/index.test-d.ts b/test/index.test-d.ts
index 68c6350e..0129f5bd 100644
--- a/test/index.test-d.ts
+++ b/test/index.test-d.ts
@@ -1,6 +1,7 @@
 import { expectError, expectType } from 'tsd'
 import { PostgrestClient, PostgrestSingleResponse } from '../src/index'
 import { SelectQueryError } from '../src/select-query-parser'
+import { Prettify } from '../src/types'
 import { Database, Json } from './types'
 
 const REST_URL = 'http://localhost:3000'
@@ -53,6 +54,31 @@ const postgrest = new PostgrestClient<Database>(REST_URL)
   expectError(postgrest.from('updatable_view').update({ non_updatable_column: 0 }))
 }
 
+// spread resource with single column in select query
+{
+  const { data, error } = await postgrest
+    .from('messages')
+    .select('message, ...users(status)')
+    .single()
+  if (error) {
+    throw new Error(error.message)
+  }
+  expectType<{ message: string | null; status: Database['public']['Enums']['user_status'] | null }>(
+    data
+  )
+}
+
+// spread resource with all columns in select query
+{
+  const { data, error } = await postgrest.from('messages').select('message, ...users(*)').single()
+  if (error) {
+    throw new Error(error.message)
+  }
+  expectType<Prettify<{ message: string | null } & Database['public']['Tables']['users']['Row']>>(
+    data
+  )
+}
+
 // json accessor in select query
 {
   const { data, error } = await postgrest