From 2fc48e9ab6cddfb0904e5582c39d3c333cba0e9e Mon Sep 17 00:00:00 2001
From: Anton Timmermans <email@atimmer.com>
Date: Wed, 21 Nov 2018 10:35:19 +0100
Subject: [PATCH] Rename emptyArray to EMPTY_ARRAY

---
 packages/annotations/src/store/selectors.js    | 17 +++++++++++++----
 packages/rich-text/src/register-format-type.js | 14 ++++++++++++--
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/packages/annotations/src/store/selectors.js b/packages/annotations/src/store/selectors.js
index f161b94a79fea7..a39a315c92f907 100644
--- a/packages/annotations/src/store/selectors.js
+++ b/packages/annotations/src/store/selectors.js
@@ -4,7 +4,16 @@
 import createSelector from 'rememo';
 import { get, flatMap } from 'lodash';
 
-const emptyArray = [];
+/**
+ * Shared reference to an empty array for cases where it is important to avoid
+ * returning a new array reference on every invocation, as in a connected or
+ * other pure component which performs `shouldComponentUpdate` check on props.
+ * This should be used as a last resort, since the normalized data should be
+ * maintained by the reducer result in state.
+ *
+ * @type {Array}
+ */
+const EMPTY_ARRAY = [];
 
 /**
  * Returns the annotations for a specific client ID.
@@ -21,12 +30,12 @@ export const __experimentalGetAnnotationsForBlock = createSelector(
 		} );
 	},
 	( state, blockClientId ) => [
-		get( state, blockClientId, emptyArray ),
+		get( state, blockClientId, EMPTY_ARRAY ),
 	]
 );
 
 export const __experimentalGetAllAnnotationsForBlock = function( state, blockClientId ) {
-	return get( state, blockClientId, [] );
+	return get( state, blockClientId, EMPTY_ARRAY );
 };
 
 /**
@@ -56,7 +65,7 @@ export const __experimentalGetAnnotationsForRichText = createSelector(
 		} );
 	},
 	( state, blockClientId ) => [
-		get( state, blockClientId, emptyArray ),
+		get( state, blockClientId, EMPTY_ARRAY ),
 	]
 );
 
diff --git a/packages/rich-text/src/register-format-type.js b/packages/rich-text/src/register-format-type.js
index 1fd7206ad5892c..262812a22b248f 100644
--- a/packages/rich-text/src/register-format-type.js
+++ b/packages/rich-text/src/register-format-type.js
@@ -11,6 +11,17 @@ import { select, dispatch, withSelect, withDispatch } from '@wordpress/data';
 import { addFilter } from '@wordpress/hooks';
 import { compose } from '@wordpress/compose';
 
+/**
+ * Shared reference to an empty array for cases where it is important to avoid
+ * returning a new array reference on every invocation, as in a connected or
+ * other pure component which performs `shouldComponentUpdate` check on props.
+ * This should be used as a last resort, since the normalized data should be
+ * maintained by the reducer result in state.
+ *
+ * @type {Array}
+ */
+const EMPTY_ARRAY = [];
+
 /**
  * Registers a new format provided a unique name and an object defining its
  * behavior.
@@ -120,8 +131,7 @@ export function registerFormatType( name, settings ) {
 
 	dispatch( 'core/rich-text' ).addFormatTypes( settings );
 
-	const emptyArray = [];
-	const getFunctionStackMemoized = memize( ( previousStack = emptyArray, newFunction ) => {
+	const getFunctionStackMemoized = memize( ( previousStack = EMPTY_ARRAY, newFunction ) => {
 		return [
 			...previousStack,
 			newFunction,