add type guard to isFbtInstance

Reviewed By: SamChou19815 Differential Revision: D54232880 fbshipit-source-id: fa68171c0deb9e6fbffa81f218e37f8370094d19
facebook · Feb 27, 2024 · 2970a2d · 2970a2d
1 parent 7b00393
commit 2970a2d
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Showing 2 changed files with 2 additions and 5 deletions.
diff --git a/flow-types/libdef/fbt.js b/flow-types/libdef/fbt.js
@@ -237,7 +237,7 @@ type $GenericFbtFunctionAPI<Input, Output, ParamInput, ParamOutput> = {
   enableJsonExportMode: () => void,
   // Only used in React Native in fbsource
   disableJsonExportMode: () => void,
-  isFbtInstance: (value: mixed) => boolean,
+  isFbtInstance: (value: mixed) => value is $FbtResultBase,
   ...
 };
 

diff --git a/runtime/shared/fbt.js b/runtime/shared/fbt.js
@@ -471,10 +471,7 @@ function disableJsonExportMode(): void {
   jsonExportMode = false;
 }
 
-// Must define this as a standalone function
-// because Flow doesn't support %check on as a class static method
-// $FlowFixMe[deprecated-type]
-function isFbtInstance(value: mixed): boolean %checks {
+function isFbtInstance(value: mixed): value is FbtResultBase {
   return value instanceof FbtResultBase;
 }