fixes #1036

src/util/object-utils.ts

@@ -59,13 +59,20 @@ export function isArrayBufferOrView(
 }
 
 export function isPlainObject(obj: unknown): obj is Record<string, unknown> {
-  return (
-    isObject(obj) &&
-    !Array.isArray(obj) &&
-    !isDate(obj) &&
-    !isBuffer(obj) &&
-    !isArrayBufferOrView(obj)
-  )
+  if (!isObject(obj) || getTag(obj) !== '[object Object]') {
+    return false
+  }
+
+  if (Object.getPrototypeOf(obj) === null) {
+    return true
+  }
+
+  let proto = obj
+  while (Object.getPrototypeOf(proto) !== null) {
+    proto = Object.getPrototypeOf(proto)
+  }
+
+  return Object.getPrototypeOf(obj) === proto
 }
 
 export function getLast<T>(arr: ArrayLike<T>): T | undefined {
@@ -169,3 +176,13 @@ function compareGenericObjects(
 
   return true
 }
+
+const toString = Object.prototype.toString
+
+function getTag(value: unknown): string {
+  if (value == null) {
+    return value === undefined ? '[object Undefined]' : '[object Null]'
+  }
+
+  return toString.call(value)
+}

test/node/src/camel-case.test.ts

@@ -1,4 +1,11 @@
-import { CamelCasePlugin, Generated, Kysely, RawBuilder, sql } from '../../../'
+import {
+  CamelCasePlugin,
+  Generated,
+  Kysely,
+  ParseJSONResultsPlugin,
+  RawBuilder,
+  sql,
+} from '../../../'
 
 import {
   destroyTest,
@@ -78,7 +85,7 @@ for (const dialect of DIALECTS) {
 
     // Can't run this test on SQLite because we can't access the same database
     // from the other Kysely instance.
-    if (dialect === 'postgres' || dialect === 'mysql' || dialect === 'mssql') {
+    if (dialect !== 'sqlite') {
       it('should have created the table and its columns in snake_case', async () => {
         const result = await sql<any>`select * from camel_person`.execute(
           ctx.db,
@@ -262,18 +269,41 @@ for (const dialect of DIALECTS) {
       })
     })
 
-    it('should respect maintainNestedObjectKeys', async () => {
-      const data = await camelDb
-        .withoutPlugins()
-        .withPlugin(new CamelCasePlugin({ maintainNestedObjectKeys: true }))
+    it('should map nested objects by default', async () => {
+      let db = camelDb.withoutPlugins()
+
+      if (dialect === 'mssql' || dialect === 'sqlite') {
+        db = db.withPlugin(new ParseJSONResultsPlugin())
+      }
+
+      db = db.withPlugin(new CamelCasePlugin())
+
+      const data = await db
         .selectFrom('camelPerson')
         .selectAll()
         .executeTakeFirstOrThrow()
 
+      expect(data.preferences).to.eql({
+        disableEmails: true,
+      })
+    })
+
+    it('should respect maintainNestedObjectKeys', async () => {
+      let db = camelDb.withoutPlugins()
+
       if (dialect === 'mssql' || dialect === 'sqlite') {
-        data.preferences = JSON.parse(data.preferences.toString())
+        db = db.withPlugin(new ParseJSONResultsPlugin())
       }
 
+      db = db.withPlugin(
+        new CamelCasePlugin({ maintainNestedObjectKeys: true }),
+      )
+
+      const data = await db
+        .selectFrom('camelPerson')
+        .selectAll()
+        .executeTakeFirstOrThrow()
+
       expect(data.preferences).to.eql({
         disable_emails: true,
       })