fix: improve typings for native module error (#479)

Author: vonovak

.gitignore

@@ -58,3 +58,7 @@ android/keystores/debug.keystore
 
 # generated by bob
 lib/
+
+
+# gh-md-toc
+docs/gh-md-toc

example/src/App.tsx

@@ -18,7 +18,7 @@ export default function App() {
     console.log(JSON.stringify(result, null, 2))
   }, [result])
 
-  const handleError = (err: Error) => {
+  const handleError = (err: unknown) => {
     if (DocumentPicker.isCancel(err)) {
       console.warn('cancelled')
       // User cancelled the picker, exit any dialogs or menus and move on
@@ -33,12 +33,15 @@ export default function App() {
     <View style={styles.container}>
       <Button
         title="open picker for single file selection"
-        onPress={() => {
-          DocumentPicker.pickSingle({
-            presentationStyle: 'fullScreen',
-          })
-            .then((pickerResult) => setResult([pickerResult]))
-            .catch(handleError)
+        onPress={async () => {
+          try {
+            const pickerResult = await DocumentPicker.pickSingle({
+              presentationStyle: 'fullScreen',
+            })
+            setResult([pickerResult])
+          } catch (e) {
+            handleError(e)
+          }
         }}
       />
       <Button

src/index.tsx

@@ -146,11 +146,22 @@ export function releaseSecureAccess(uris: Array<string>): Promise<void> {
 const E_DOCUMENT_PICKER_CANCELED = 'DOCUMENT_PICKER_CANCELED'
 const E_DOCUMENT_PICKER_IN_PROGRESS = 'ASYNC_OP_IN_PROGRESS'
 
-export function isCancel(err: Error & { code?: string }): boolean {
-  return err?.code === E_DOCUMENT_PICKER_CANCELED
+export type NativeModuleErrorShape = Error & { code?: string }
+
+export function isCancel(err: unknown): boolean {
+  return isErrorWithCode(err, E_DOCUMENT_PICKER_CANCELED)
+}
+
+export function isInProgress(err: unknown): boolean {
+  return isErrorWithCode(err, E_DOCUMENT_PICKER_IN_PROGRESS)
 }
-export function isInProgress(err: Error & { code?: string }): boolean {
-  return err?.code === E_DOCUMENT_PICKER_IN_PROGRESS
+
+function isErrorWithCode(err: unknown, errorCode: string): boolean {
+  if (err instanceof Error && 'code' in err) {
+    const nativeModuleErrorInstance = err as NativeModuleErrorShape
+    return nativeModuleErrorInstance?.code === errorCode
+  }
+  return false
 }
 
 export default {