From 3d6bb88556441860877d3e7befe10c2727423026 Mon Sep 17 00:00:00 2001
From: Severiano Badajoz <sbadajoz@chanzuckerberg.com>
Date: Mon, 15 Jul 2019 16:00:23 -0700
Subject: [PATCH] improve performance around category highlighting (#849)

* remove function call and add comment

* separate crossfilter size calc into memoized function
---
 client/src/components/graph/graph.js | 17 +++++++++++++++--
 client/src/reducers/centroidLabel.js |  4 ++--
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/client/src/components/graph/graph.js b/client/src/components/graph/graph.js
index b5959a28..09cadd13 100644
--- a/client/src/components/graph/graph.js
+++ b/client/src/components/graph/graph.js
@@ -52,16 +52,27 @@ class Graph extends React.Component {
     return colors;
   });
 
+  computePointSizesFromCrossfilter = memoize((len, crossfilter) => {
+    const sizes = new Float32Array(len);
+    crossfilter.fillByIsSelected(sizes, 4, 0.2);
+
+    return sizes;
+  });
+
   computePointSizes = memoize(
     (len, crossfilter, metadataField, categoryField) => {
       /*
     compute webgl dot size for each point
     */
 
-      const sizes = new Float32Array(len);
-      crossfilter.fillByIsSelected(sizes, 4, 0.2);
+      const selectionSizes = this.computePointSizesFromCrossfilter(
+        len,
+        crossfilter
+      );
+      let sizes;
 
       if (metadataField && categoryField) {
+        sizes = selectionSizes.slice();
         const valuesArr = crossfilter.data.col(metadataField).asArray();
 
         for (let i = 0; i < len; i += 1) {
@@ -69,6 +80,8 @@ class Graph extends React.Component {
             sizes[i] = 10;
           }
         }
+      } else {
+        sizes = selectionSizes;
       }
       return sizes;
     }
diff --git a/client/src/reducers/centroidLabel.js b/client/src/reducers/centroidLabel.js
index 5582e5cc..c1060fb6 100644
--- a/client/src/reducers/centroidLabel.js
+++ b/client/src/reducers/centroidLabel.js
@@ -19,12 +19,12 @@ const CentroidLabel = (state = initialState, action, sharedNextState) => {
         metadataField,
         categoryIndex,
         categoryField,
-        centroidXY: calcCentroid(
+        centroidXY: null /* calcCentroid(  This function call is computationally heavy and also leading to large GC. Before reimplementation, look into optimization and memoization
           world,
           metadataField,
           categoryField,
           layoutChoice.currentDimNames
-        )
+        ) */
       };
 
     case "category value mouse hover end":