From 037fbe55806aa4cbf353211bb5175237c3eb9807 Mon Sep 17 00:00:00 2001
From: Valeri Karpov <val@karpov.io>
Date: Sun, 8 Sep 2019 16:02:33 -0600
Subject: [PATCH] refactor(populate): assign using all separate models after
 all queries are done re: #3812

---
 lib/model.js | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/lib/model.js b/lib/model.js
index d9a5b176a95..a9a0784c50e 100644
--- a/lib/model.js
+++ b/lib/model.js
@@ -4190,16 +4190,7 @@ function populate(model, docs, options, callback) {
       mod.options.options.limit = mod.options.options.limit * ids.length;
     }
 
-    params.push([mod, match, select, assignmentOpts, (err, valsFromDb) => {
-      if (err != null) {
-        return callback(err, null);
-      }
-      vals = vals.concat(valsFromDb);
-      if (--_remaining === 0) {
-        _assign(model, vals, mod, assignmentOpts);
-        callback();
-      }
-    }]);
+    params.push([mod, match, select, assignmentOpts, _next]);
   }
 
   if (!hasOne) {
@@ -4209,6 +4200,25 @@ function populate(model, docs, options, callback) {
   for (const arr of params) {
     _execPopulateQuery.apply(null, arr);
   }
+
+  function _next(err, valsFromDb) {
+    if (err != null) {
+      return callback(err, null);
+    }
+    vals = vals.concat(valsFromDb);
+    if (--_remaining === 0) {
+      _done();
+    }
+  }
+
+  function _done() {
+    for (const arr of params) {
+      const mod = arr[0];
+      const assignmentOpts = arr[3];
+      _assign(model, vals, mod, assignmentOpts);
+    }
+    callback();
+  }
 }
 
 /*!