A small but useful category method on UIWebView: Turn uncaught JavaScript Exception into a NSError!
1//
2// Created by Marcus Rohrmoser on 05.12.13.
3// Copyright (c) 2013 Marcus Rohrmoser mobile Software. All rights reserved.
4//
5
6#import "UIWebView+JavaScriptNSError.h"
7
8#define NSERROR_UIWEBVIEW_SCRIPT @"NSERROR_UIWEBVIEW_SCRIPT"
9#define NSERROR_UIWEBVIEW_SCRIPT_CODE 1
10
11@implementation UIWebView(JavaScriptNSError)
12
13-(NSString *)stringByEvaluatingJavaScriptFromString:(NSString *)script error:(NSError * __autoreleasing *)error
14{
15 NSString *errorPrefix = NSERROR_UIWEBVIEW_SCRIPT;
16 NSString *exec = [NSString stringWithFormat:@"try { %@ } catch (e) { '%@' + e; }", script, errorPrefix, nil];
17 NSString *ret = [self stringByEvaluatingJavaScriptFromString:exec];
18
19 if( ![ret hasPrefix:errorPrefix] )
20 return ret;
21
22 if( error ) {
23 NSString *msg = [ret substringFromIndex:errorPrefix.length];
24 NSDictionary *ui = @ {
25 NSLocalizedDescriptionKey: msg,
26 NSFilePathErrorKey:[self.request.URL absoluteString],
27 NSURLErrorKey: self.request.URL,
28 NSLocalizedFailureReasonErrorKey: msg,
29 NSURLErrorFailingURLErrorKey: self.request.URL,
30 NSURLErrorFailingURLStringErrorKey: self.request.URL
31 };
32 *error = [NSError errorWithDomain:NSERROR_UIWEBVIEW_SCRIPT code:NSERROR_UIWEBVIEW_SCRIPT_CODE userInfo:ui];
33 }
34 return nil;
35}
36@end
