Fix defaulting type errors

Author: kitten

packages/react-native/scripts/codegen/generate-artifacts-executor/index.js

@@ -210,29 +210,38 @@ function readOutputDirFromPkgJson(
 
 function computeOutputPath(
   projectRoot /*: string */,
-  baseOutputPath /*: string | void | null */,
+  optionalBaseOutputPath /*: string | void | null */,
   pkgJson /*: $FlowFixMe */,
   platform /*: string */,
-) {
-  if (baseOutputPath == null) {
+) /*: string */ {
+  let baseOutputPath /*: string */;
+  if (optionalBaseOutputPath == null) {
     const outputDirFromPkgJson = readOutputDirFromPkgJson(pkgJson, platform);
     if (outputDirFromPkgJson != null) {
-      // $FlowFixMe[reassign-const]
       baseOutputPath = path.join(projectRoot, outputDirFromPkgJson);
     } else {
-      // $FlowFixMe[reassign-const]
       baseOutputPath = projectRoot;
     }
+  } else {
+    baseOutputPath = optionalBaseOutputPath;
   }
   if (pkgJsonIncludesGeneratedCode(pkgJson)) {
     // Don't create nested directories for libraries to make importing generated headers easier.
     return baseOutputPath;
   }
   if (platform === 'android') {
-    return defaultOutputPathForAndroid(baseOutputPath);
+    return defaultOutputPathForAndroid(
+      baseOutputPath != null && baseOutputPath.length > 0
+        ? baseOutputPath
+        : projectRoot,
+    );
   }
   if (platform === 'ios') {
-    return defaultOutputPathForIOS(baseOutputPath);
+    return defaultOutputPathForIOS(
+      baseOutputPath != null && baseOutputPath.length > 0
+        ? baseOutputPath
+        : projectRoot,
+    );
   }
   return baseOutputPath;
 }

packages/react-native/scripts/codegen/generate-artifacts-executor/utils.js

@@ -104,7 +104,9 @@ function readGeneratedAutolinkingOutput(
   // NOTE: Generated by scripts/cocoapods/autolinking.rb in list_native_modules (called by use_native_modules)
   // The `baseOutputPath` is based on a CLI argument and optional
   const autolinkingGeneratedPath = path.resolve(
-    baseOutputPath || projectRoot,
+    baseOutputPath != null && baseOutputPath.length > 0
+      ? baseOutputPath
+      : projectRoot,
     'build/generated/autolinking/autolinking.json',
   );
   if (fs.existsSync(autolinkingGeneratedPath)) {