Small Javascript Debugger

Recently faced in research with the project trimpath . For myself, I did not find anything interesting, except for an interesting way of setting breakpoints (I modified it a bit from the original - otherwise the long lines were incorrectly displayed in the opera and IA)

breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .

1. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
2. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
3. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
4. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
5. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
6. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
7. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
8. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
9. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
10. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
11. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
12. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
13. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
14. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
15. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
16. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
17. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
18. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
19. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
20. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
21. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
22. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
23. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
24. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
25. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
26. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
27. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
28. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
29. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
30. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
31. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
32. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
33. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .
35. breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .

breakpoint = function (_name, _context) { if (!breakpoint.allow) { return ; } var expr, result, output; while ( true ) { expr = prompt( 'Debug into breakpoint "' + _name + '"' , '' ); if (!expr) { break ; } else { output = true ; try { result = result = _context(expr); } catch (e) { alert( '[!] caught exception with message "' + e.message + '"' ); output = false ; } if (output) { alert(result); } } } } breakpoint.allow = true ; * This source code was highlighted with Source Code Highlighter .

Now, to put a breakpoint current, you need to write something like this:
')

1. function f (_a, _b, _c)
2. {
3. var a = 10;
4. var b = 20;
5. var c = 30;
6. breakpoint ( "breakpoint1" , function (_ $) { return eval (_ $);});
7. }
9. f (40, 50, 60);

* This source code was highlighted with Source Code Highlighter .

Pay attention to the function function (_ $) {return eval (_ $); } - so the context of the calling function is passed to the breakpoint. The name _ $ is used as a rarely encountered identifier.

This mechanism can be useful where there is no firebug or other normal debuggers, for example, in IA. Simple and tasteful. : ^)

I apologize if I wrote the dupe - for me it was a new approach.

UPD # 1 12/08/09

If you change the breakpoint code like this:

1. debug = true ;
3. breakpoint = '(new Breakpoint (\' anonymous \ ')). exec (function (_ $) {return eval (_ $);});' ;
5. Breakpoint = function (_name)
6. {
7. this .name = _name? 'anonymous' : _name;
8. this .allow = true ;
9. }
11. Breakpoint.prototype.exec = function (_context)
12. {
13. if (! (debug && this .allow))
14. {
15. return ;
16. }
17. ...
18. }

* This source code was highlighted with Source Code Highlighter .

you can write like this:

1. eval (breakpoint);

* This source code was highlighted with Source Code Highlighter .

Thanks asmolianinov for the idea (see comments).