Handle nullish values in processBoxShadow and processFilter

Summary:
Viewconfig processors may still get called for nullish values I think. Most other processors explicitly handle these (but some don't??).

This returns an empty list, like on parse error, when we have a value, but the value is nullish.

Changelog: [Internal]

Reviewed By: joevilches

Differential Revision: D59933611

fbshipit-source-id: 3f1d89d21977bbe01a05e708aadf1a9451d88083

packages/react-native/Libraries/StyleSheet/processBoxShadow.js

@@ -24,9 +24,12 @@ export type ParsedBoxShadow = {
 };
 
 export default function processBoxShadow(
-  rawBoxShadows: $ReadOnlyArray<BoxShadowPrimitive> | string,
+  rawBoxShadows: ?($ReadOnlyArray<BoxShadowPrimitive> | string),
 ): Array<ParsedBoxShadow> {
   const result: Array<ParsedBoxShadow> = [];
+  if (rawBoxShadows == null) {
+    return result;
+  }
 
   const boxShadowList =
     typeof rawBoxShadows === 'string'

packages/react-native/Libraries/StyleSheet/processFilter.js

@@ -36,9 +36,13 @@ type ParsedDropShadow = {
 };
 
 export default function processFilter(
-  filter: $ReadOnlyArray<FilterFunction> | string,
+  filter: ?($ReadOnlyArray<FilterFunction> | string),
 ): $ReadOnlyArray<ParsedFilter> {
   let result: Array<ParsedFilter> = [];
+  if (filter == null) {
+    return result;
+  }
+
   if (typeof filter === 'string') {
     // matches on functions with args like "drop-shadow(1.5)"
     const regex = /([\w-]+)\(([^)]+)\)/g;

packages/react-native/Libraries/__tests__/__snapshots__/public-api-test.js.snap

@@ -8875,7 +8875,7 @@ exports[`public API should not change unintentionally Libraries/StyleSheet/proce
   inset?: boolean,
 };
 declare export default function processBoxShadow(
-  rawBoxShadows: $ReadOnlyArray<BoxShadowPrimitive> | string
+  rawBoxShadows: ?($ReadOnlyArray<BoxShadowPrimitive> | string)
 ): Array<ParsedBoxShadow>;
 "
 `;
@@ -8916,7 +8916,7 @@ type ParsedDropShadow = {
   color?: ColorValue,
 };
 declare export default function processFilter(
-  filter: $ReadOnlyArray<FilterFunction> | string
+  filter: ?($ReadOnlyArray<FilterFunction> | string)
 ): $ReadOnlyArray<ParsedFilter>;
 "
 `;