Added method absolutePath:inStorage

Author: Preben Ludviksen

ios/RNFileSystem/RNFileSystem.h

@@ -13,6 +13,7 @@ extern NSString *const STORAGE_TEMPORARY;
 + (BOOL)fileExists:(NSString*)relativePath inStorage:(NSString*)storage;
 + (BOOL)directoryExists:(NSString*)relativePath inStorage:(NSString*)storage;
 + (BOOL)deleteFileOrDirectory:(NSString*)relativePath inStorage:(NSString*)storage;
++ (NSString*)absolutePath:(NSString*)relativePath inStorage:(NSString*)storage;
 
 // Extra method for integration from other modules / native code
 + (NSString*)moveFileFromUrl:(NSURL*)location toRelativePath:(NSString*)relativePath inStorage:(NSString*)storage;

ios/RNFileSystem/RNFileSystem.m

@@ -96,6 +96,11 @@ + (BOOL)addSkipBackupAttributeToItemAtPath:(NSString *) filePathString
   return success;
 }
 
++ (NSString*)absolutePath:(NSString*)relativePath inStorage:(NSString*)storage {
+  NSURL *baseDir = [RNFileSystem baseDirForStorage:storage];
+  return [[baseDir URLByAppendingPathComponent:relativePath] path];
+}
+
 // Extra method for integration from other modules / native code
 + (NSString*)moveFileFromUrl:(NSURL*)location toRelativePath:(NSString*)relativePath inStorage:(NSString*)storage {
   NSFileManager *fileManager = [NSFileManager defaultManager];