ECMAscript v5/Strict complience

[AlyxRen]

ES5/Strict requires that you put at the top of the function call the string literal "use strict";
While theres only one current implementation of strict mode ( http://besen.sourceforge.net/ ),
it would be useful to allow the parser to check if the first line of your coffee is the string "use strict" and place it above all the var declarations in the final converted js

[jashkenas]

Hmm. Instead of forcing people to litter their code with "use strict" at the top of every file, perhaps CoffeeScript should add "use strict"; to every output file automatically, once there are enough browsers / runtimes supporting it. Is there ever a situation where you wouldn't want strict mode in CoffeeScript, given that it makes the execution of your code a good deal faster?

[AlyxRen]

That makes perfect sense.

[jashkenas]

Great, closing this ticket for the time being. We'll re-open it / implement it when browsers are ready.

[AlyxRen]

Sounds like a plan, I'll update when browsers trickle in support for strict mode.

[banksJeremy]

Chrome, Safari and Firefox now support strict mode, and Internet Explorer 10 will as well. Is this worth doing now?

[michaelficarra]

Strict mode support isn't exactly complete in current engines, but it's a lot better than last year, so re-opening. Related: #1547 and #1534.

[paulmillr]

👍 (+1)

[tpetry]

+1 for automatic strict mode compilation for every CS-File

[jashkenas]

Turns out that strict mode doesn't actually enable any code optimizations in current generation browsers ... it adds extra checks that make it slower, if anything. Closing as a wontfix until strict mode start showing benefits.

[michaelficarra]

I predict we will be waiting around another year for the browsers to actually execute strict mode code quickly. sigh...

[vinyll]

ok, 2 years for now. strict mode is in. +1 to go for it

[vendethiel]

I think it's faster now :).

[hden]

👍

[GeoffreyBooth]

See 2337.