Return file contents to JavaScript from Objective-C

return.m

- (void) restClient:(DBRestClient*)client loadedFile:(NSString*)localPath {
    NSLog(@"File loaded into path: %@", localPath);
    
    NSData *fileData;
    fileData = [NSData dataWithContentsOfFile:localPath];
    if (!fileData){
        NSLog(@"Error - File not found");
    }
    NSString* fileString = [[NSString alloc] initWithData:fileData encoding:NSUTF8StringEncoding];
    AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
    NSString *jsCallback = [[NSString alloc] initWithFormat:@"showFileContents('%@')", fileString];
    [appDelegate.viewController.webView stringByEvaluatingJavaScriptFromString:jsCallback]; // this calls showFileContents function in JS and sends it the fileString as a parameter
    
    [self writeJavascript:restoreJavaScript]; // return code to execute JavaScript function after file is downloaded
}