From 3d26c74b6262aa387ba72032ed0c5ffc867ce4a3 Mon Sep 17 00:00:00 2001
From: Theodor Diaconu <diaconu.theodor@gmail.com>
Date: Sat, 7 Jul 2018 09:10:31 +0300
Subject: [PATCH] Performance fixes for assembler

---
 lib/query/hypernova/assembler.js | 56 +++++++++++++++++++++++++-------
 1 file changed, 44 insertions(+), 12 deletions(-)

diff --git a/lib/query/hypernova/assembler.js b/lib/query/hypernova/assembler.js
index 33679eb..a02d1d5 100644
--- a/lib/query/hypernova/assembler.js
+++ b/lib/query/hypernova/assembler.js
@@ -20,13 +20,51 @@ export default (childCollectionNode, {limit, skip, metaFilters}) => {
         })
     }
 
-    _.each(parent.results, result => {
-        let data = assembleData(childCollectionNode, result, {
-            fieldStorage, strategy, isSingle
-        });
+    const resultsByKeyId = _.groupBy(childCollectionNode.results, '_id');
 
-        result[childCollectionNode.linkName] = filterAssembledData(data, {limit, skip})
-    });
+    if (strategy === 'one') {
+        parent.results.forEach(parentResult => {
+            parentResult[childCollectionNode.linkName] = 
+                filterAssembledData(
+                    resultsByKeyId[parentResult[fieldStorage]],
+                    {limit, skip}
+                )
+        })
+    }
+
+    if (strategy === 'many') {
+        parent.results.forEach(parentResult => {
+            let data = [];
+            parentResult[fieldStorage].forEach(_id => {
+                data.push(resultsByKeyId[_id]);
+            })
+
+            parentResult[childCollectionNode.linkName] = filterAssembledData(data, {limit, skip});
+        })
+    }
+
+    if (strategy === 'one-meta') {
+        parent.results.forEach(parentResult => {
+            parentResult[childCollectionNode.linkName] = 
+                filterAssembledData(
+                    resultsByKeyId[parentResult[fieldStorage]._id],
+                    {limit, skip}
+                )
+        })
+    }
+
+
+    if (strategy === 'many-meta') {
+        parent.results.forEach(parentResult => {
+            const _ids = _.pluck(parentResult[fieldStorage], '_id');
+            let data = [];
+            _ids.forEach(_id => {
+                data.push(resultsByKeyId[_id]);
+            })
+
+            parentResult[childCollectionNode.linkName] = filterAssembledData(data, {limit, skip});
+        })
+    }
 }
 
 function filterAssembledData(data, {limit, skip}) {
@@ -36,9 +74,3 @@ function filterAssembledData(data, {limit, skip}) {
 
     return data;
 }
-
-function assembleData(childCollectionNode, result, {fieldStorage, strategy}) {
-    const filters = createSearchFilters(result, fieldStorage, strategy, false);
-
-    return sift(filters, childCollectionNode.results);
-}