From b99f6d37f00f49a2de38d6b777fced781995c57a Mon Sep 17 00:00:00 2001
From: Valeri Karpov <val@karpov.io>
Date: Sun, 10 May 2020 13:08:40 -0400
Subject: [PATCH] BREAKING CHANGE: make `MongooseArray#map()` return a plain
 JavaScript array rather than a headless Mongoose array

Re: #8356
---
 lib/plugins/idGetter.js          | 4 +++-
 lib/types/documentarray.js       | 7 ++-----
 test/types.documentarray.test.js | 5 +++--
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/lib/plugins/idGetter.js b/lib/plugins/idGetter.js
index 39254c0074e..f432a83288a 100644
--- a/lib/plugins/idGetter.js
+++ b/lib/plugins/idGetter.js
@@ -11,10 +11,12 @@ module.exports = function addIdGetter(schema) {
     !schema.options.noVirtualId &&
     schema.options.id;
   if (!autoIdGetter) {
-    return;
+    return schema;
   }
 
   schema.virtual('id').get(idGetter);
+
+  return schema;
 };
 
 /*!
diff --git a/lib/types/documentarray.js b/lib/types/documentarray.js
index 35d152859a6..72dfa95fc23 100644
--- a/lib/types/documentarray.js
+++ b/lib/types/documentarray.js
@@ -39,12 +39,9 @@ class CoreDocumentArray extends CoreMongooseArray {
    */
 
   map() {
-    const ret = super.map.apply(this, arguments);
-    ret[arraySchemaSymbol] = null;
-    ret[arrayPathSymbol] = null;
-    ret[arrayParentSymbol] = null;
+    const copy = [].concat(this);
 
-    return ret;
+    return Array.prototype.map.apply(copy, arguments);
   }
 
   /**
diff --git a/test/types.documentarray.test.js b/test/types.documentarray.test.js
index 8cf6529125a..c5ee41248bf 100644
--- a/test/types.documentarray.test.js
+++ b/test/types.documentarray.test.js
@@ -10,6 +10,7 @@ const DocumentArray = require('../lib/types/documentarray');
 const ArraySubdocument = require('../lib/types/ArraySubdocument');
 const assert = require('assert');
 const co = require('co');
+const idGetter = require('../lib/plugins/idGetter');
 const setValue = require('../lib/utils').setValue;
 
 const mongoose = require('./common').mongoose;
@@ -39,7 +40,7 @@ function TestDoc(schema) {
     title: { type: String }
   });
 
-  Subdocument.prototype.$__setSchema(schema || SubSchema);
+  Subdocument.prototype.$__setSchema(idGetter(schema || SubSchema));
 
   return Subdocument;
 }
@@ -575,7 +576,7 @@ describe('types.documentarray', function() {
       assert.equal(doc.docs.length, 2);
     });
 
-    it('map() works', function() {
+    it('map() works (gh-8317)', function() {
       const personSchema = new Schema({ friends: [{ name: { type: String } }] });
       mongoose.deleteModel(/Test/);
       const Person = mongoose.model('Test', personSchema);