4 ms·

I don't know much about how to architect JavaScript applications, but I am struck by how much of this stuff seems to be glued together by strings. For example,

I don't know much about how to architect JavaScript applications, but I am struck by how much of this stuff seems to be glued together by strings. For example, from footer.js (https://github.com/box/t3js/blob/master/examples/todo/js/modules/footer.js https://github.com/box/t3js/blob/master/examples/todo/js/mod...) switch(name) { case 'todoadded': case 'todoremoved': case 'todostatuschange': this.updateTodoCounts(); break; case 'statechanged': this.updateSelectedFilterByUrl(data.url); break; } Accidentally wrote 'todostatuschanged' instead of 'todostatuschange' (in keeping with the tense of all the other actions!) and you'll get a silent failure. Or from isListCompleted() in the list module: moduleEl.querySelectorAll('#todo-list li input[type="checkbox"]') I'm not picking on T3, since all JavaScript frameworks seem to have this problem. There has to be a better way than that!

glibgil 12y ago
Yes, it is called static analysis http://en.wikipedia.org/wiki/Static_program_analysis http://en.wikipedia.org/wiki/Static_program_analysis. It exists for JavaScript: https://github.com/sinelaw/infernu https://github.com/sinelaw/infernu https://github.com/facebook/flow https://github.com/facebook/flow
- reverius42 12y ago
  I don't see how static analysis helps the switch-case on strings. It might, if JS had a more expressive (static) type system. An enum type, perhaps?
  - gnud 12y ago
    I usually do something like var Constants = { valueA: function valueA() {}, valueB: function valueB() {} };
    - Mister_Snuggles 12y ago
      Why do you use empty functions instead of a number or a string?
      - madeofpalk 12y ago
        My guess is than a function will always be a unique object, rather than if it was a number or string, there's a chance you use the same value twice.
        gingerrr 12y ago
        an object literal would provide the same guarantee but without the overhead of function prototype methods, wonder if there's any other reason?
        drifkin 12y ago
        Maybe they're using functions so the values can have names? Perhaps easier to debug.
    - anewhnaccount 12y ago
      In ES6 you can use Symbol.
  - glibgil 12y ago
    If you have static analysis then it makes sense to use types instead of strings. If you don't have static analysis then there isn't much motivation which is why you see strings everywhere in unanalyzed JavaScript.
- duaneb 12y ago
  Neither of those implement a type where you can enumerate the values exhaustively.
- mlvljr 12y ago
  Bad fanboy! BAD!
Ciantic 12y ago
You should try WebSharper http://websharper.com/ http://websharper.com/, it generates JavaScript out of F#.

glibgil 12y ago

Yes, it is called static analysis http://en.wikipedia.org/wiki/Static_program_analysis http://en.wikipedia.org/wiki/Static_program_analysis. It exists for JavaScript: https://github.com/sinelaw/infernu https://github.com/sinelaw/infernu https://github.com/facebook/flow https://github.com/facebook/flow

reverius42 12y ago
I don't see how static analysis helps the switch-case on strings. It might, if JS had a more expressive (static) type system. An enum type, perhaps?
- gnud 12y ago
  I usually do something like var Constants = { valueA: function valueA() {}, valueB: function valueB() {} };
  - Mister_Snuggles 12y ago
    Why do you use empty functions instead of a number or a string?
    - madeofpalk 12y ago
      My guess is than a function will always be a unique object, rather than if it was a number or string, there's a chance you use the same value twice.
      - gingerrr 12y ago
        an object literal would provide the same guarantee but without the overhead of function prototype methods, wonder if there's any other reason?
        drifkin 12y ago
        Maybe they're using functions so the values can have names? Perhaps easier to debug.
  - anewhnaccount 12y ago
    In ES6 you can use Symbol.
- glibgil 12y ago
  If you have static analysis then it makes sense to use types instead of strings. If you don't have static analysis then there isn't much motivation which is why you see strings everywhere in unanalyzed JavaScript.
duaneb 12y ago
Neither of those implement a type where you can enumerate the values exhaustively.
mlvljr 12y ago
Bad fanboy! BAD!

Ciantic 12y ago

You should try WebSharper http://websharper.com/ http://websharper.com/, it generates JavaScript out of F#.