chore: add comment

Author: avallete

src/types.ts

@@ -161,7 +161,12 @@ type MergeExplicit<New, Row> = {
 }
 
 type MergeDeep<New, Row> = Simplify<
-  MergeExplicit<New, Row> & (string extends keyof Row ? { [K: string]: Row[string] } : {})
+  MergeExplicit<New, Row> &
+    // Intersection here is to restore dynamic keys into the merging result
+    // eg:
+    // {[key: number]: string}
+    // or Record<string, number | null>
+    (string extends keyof Row ? { [K: string]: Row[string] } : {})
 >
 
 // Helper to check if a type is a plain object (not an array)

test/override-types.test-d.ts

@@ -247,6 +247,7 @@ const postgrest = new PostgrestClient<Database>(REST_URL)
           bar: { baz: number }
           en: 'ONE' | 'TWO' | 'THREE'
           record: Record<string, Json | undefined> | null
+          recordNumber: Record<number, Json | undefined> | null
           qux: boolean
         }
         age_range: unknown
@@ -277,6 +278,7 @@ const postgrest = new PostgrestClient<Database>(REST_URL)
           bar: { baz: number }
           en: 'ONE' | 'TWO' | 'THREE'
           record: Record<string, Json | undefined> | null
+          recordNumber: Record<number, Json | undefined> | null
           qux: boolean
         } | null
         age_range: unknown
@@ -345,6 +347,7 @@ const postgrest = new PostgrestClient<Database>(REST_URL)
           bar: { baz: number; newBaz: string }
           en: 'FOUR' // Overridden enum value
           record: Record<string, Json | undefined> | null
+          recordNumber: Record<number, Json | undefined> | null
         }
         age_range: unknown
         catchphrase: unknown
@@ -359,7 +362,7 @@ const postgrest = new PostgrestClient<Database>(REST_URL)
   const result = await postgrest
     .from('users')
     .select()
-    .overrideTypes<{ data: { record: { baz: 'foo' } } }[]>()
+    .overrideTypes<{ data: { record: { baz: 'foo' }; recordNumber: { bar: 'foo' } } }[]>()
   if (result.error) {
     throw new Error(result.error.message)
   }
@@ -379,6 +382,10 @@ const postgrest = new PostgrestClient<Database>(REST_URL)
             [x: string]: Json | undefined
             baz: 'foo'
           }
+          recordNumber: {
+            [x: number]: Json | undefined
+            bar: 'foo'
+          }
         }
         age_range: unknown
         catchphrase: unknown

test/types.ts

@@ -7,6 +7,7 @@ export type CustomUserDataType = {
   }
   en: 'ONE' | 'TWO' | 'THREE'
   record: Record<string, Json | undefined> | null
+  recordNumber: Record<number, Json | undefined> | null
 }
 
 export type Database = {