From cd635dcecae9e51ecd1d2a2e867971829ab8056f Mon Sep 17 00:00:00 2001
From: Chris Beer <cabeer@stanford.edu>
Date: Mon, 15 Apr 2019 13:44:25 -0700
Subject: [PATCH] Add special memoizing logic to getLocales to keep providing
the same array each call
---
src/state/selectors/manifests.js | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/src/state/selectors/manifests.js b/src/state/selectors/manifests.js
index 28a96ade9..095cd40fe 100644
--- a/src/state/selectors/manifests.js
+++ b/src/state/selectors/manifests.js
@@ -1,5 +1,6 @@
-import { createSelector } from 'reselect';
+import { createSelector, createSelectorCreator } from 'reselect';
import manifesto, { LanguageMap } from 'manifesto.js';
+import memoize from 'lodash/memoize';
import ManifestoCanvas from '../../lib/ManifestoCanvas';
/** Get the relevant manifest information */
@@ -346,7 +347,15 @@ function getLocales(resource) {
return Object.keys(languages);
}
-export const getMetadataLocales = createSelector(
+/** */
+const manifestHashFn = manifest => manifest && manifest.id;
+// this has the potential to be an annoying memory leak, because the memoize store will grow
+// unbounded.
+const manifestMemoizingSelectorCreator = createSelectorCreator(memoize, manifestHashFn);
+
+// this is specially memoized because getLocales is creating new array instances
+// every time it is called.
+export const getMetadataLocales = manifestMemoizingSelectorCreator(
[getManifestoInstance],
manifest => getLocales(manifest),
);
--
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