CoffeeScript preferred styles

[jasonramirez]

Prefer @ over this for referencing instance properties

Prefer double quotes to preserve interpolation, allow for more complex strings, make selectors easier to read and for overall consistency.

• $("[data-role='title']") or $("input[type='text']")
• "Isn't this nice?"
• "It is #{nice}"

[gabebw]

What do you mean by "for scoping"? Can you give an example of when we don't prefer @ to this?

[drapergeek]

I think we can simplify this to just read, 'Prefer @ to this'. I don't know of any situation in coffeescript that using this is preferred over @.

[jferris]

I've used @ for properties, but not for passing the instance itself. For example:

new Post user: @

I would use this instead of @ there.

[gabebw]

I've used it for passing the instance itself. I got used to it, but I'd really just prefer to have a guideline.

I do think that "Always use @" is a simpler guideline, which has value.

[jessieay]

I like 'Prefer @ to this' (suggestion from @drapergeek )

[jasonramirez]

@gabebw the notion to use @ instead of this may be more about context..not scoping. I was trying to state that we should use @ when in reference to the object that 'owns' the currently executing code. This conversation came about when a client asked why we do:

constructor: ->
  @someMethod()

vs.

constructor: ->
  this.someMethod()

So perhaps:
When referencing properties, use @ instead of this
or
Use @ instead of this, unless passing the instance itself.

[mcmire]

I agree with Joe. Instead of a broad rule like "use @ anywhere you'd use this", I would prefer something more specific like "Prefer @ over this for referencing instance properties". It honestly looks weird to me to see @ standalone. I've seen this happen generally in two cases:

$(@) (for $(this)):

$('.some_selector').on 'click', ->
  $(@).hide()

@ as the final line of a method (for returning this):

class Foo
  set: (properties) ->
    _.extend this, properties
    @

I have two reasons for using a more specific guideline:

1. Only using @ for instance attributes and methods feels more like Ruby, so it's less of a context switch.
2. For a while it was actually discouraged and Jeremy Ashkenas briefly considered removing support for bare @ in CoffeeScript (discussion), but ultimately nothing was done because of the controversy around it. Perhaps a weak point, although, it's been removed in the upcoming "CoffeeScriptRedux".

[mcmire]

So yeah, basically what Jason said.

[gabebw]

Elliot, I like Prefer @ over this for referencing instance properties. It doesn't say anything about using @ or this when passing the instance, but makes it clear when we do care.

That guideline gets my vote.

[kaishin]

I use single quotes, except for when I interpolate. Example:

class App.SuggestionListView extends Backbone.View
  ACTIVE_CLASS = 'active'
  SUGGESTION_SELECTOR = '[data-role="suggestion"]'
  updateTranslation: (selectedSuggestion) ->
    $activeSuggestions = $(".#{ACTIVE_CLASS}")

They are twice as fast to type and are easier on the eyes.

I think we should leave this as a per-project matter, just like HAML vs HTML.

[kaishin]

Twice as fast -> Require half the effort ;)

[jasonramirez]

@kaishin I have no problem leaving it as a per-project matter. I was looking through the CoffeeScript in our past projects, and we've done a mix of both versions of quoting, so I was hoping to get some preference for consistency. Something like (i think) we do in Ruby, where we use single quotes unless we have to use double quotes, seems like where we are.

I will put this part to bed if nobody finds value in setting a preference.

No Preference:

a = 'They Are'
b = "They're"
c = "[data-role='suggestion']"
d = '[data-role="content"]'
e = "#{whoops}"

Double Quote Preference:

a = "They Are"
b = "They're"
c = "[data-role='suggestion']"
d = "[data-role='content']"
e = "#{whoops}"

[mcmire]

I would prefer consistency between our Ruby guides and CoffeeScript guides. So whatever guideline we currently have there (single quotes are still preferred, I believe), then we should make the same guideline here.

[dgalarza]

I agree with @mcmire. I think we should be consistent with our style between CoffeeScript and Ruby with things like quotation marks.

[sgrif]

Keep in mind, it looks like the ruby guide is about to switch to double quotes. #174

[kaishin]

I can live with double quotes in Coffeescript.

[jferris]

Unless there's a strong reason to diverge, I'd prefer to be consistent with what we're doing in Ruby.

[mxie]

Yes, double quotes for all!

[sgrif]

Should we promote this to a generic "if your language supports both single
and double quotes..."?
On Jun 16, 2014 8:33 AM, "Melissa Xie" [email protected] wrote:

Yes, double quotes for all!

—
Reply to this email directly or view it on GitHub
#187 (comment).

[jferris]

Should we promote this to a generic "if your language supports both single
and double quotes..."?

Would you think to check both "Coffeescript" and "Generic" sections? I'm not sure that I would.

[mcmire]

I think it's fine to keep guidelines separate for each language. There are people who know Ruby but not CoffeeScript and vice versa (not among us, likely, but elsewhere).

[jasonramirez]

+1 for keeping this specific to each language

[jferris]

Any objections to merging this as-is?

[sgrif]

👍

[mcmire]

I'm in favor.

[jasonramirez]

Merging