new rule: space before (certain) keywords

[dwelle]

There's a rule for space-after-keywords, but it seems to me it enforces just one half of the same styleguide, because it doesn't require space before keywords like else, catch, and finally.

if ( a ) {} else{}; // space after `else` is enforced
if ( a ) {}else {}; // while space before `else` is not enforced

Therefore, we probably should have a rule like space-before-keywords.

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[nzakas]

You're right, though might be better to have a single rule do both.

[dwelle]

agreed

[michaelficarra]

Just space-keywords.

[gcochard]

Config for this should look something like:

"space-keywords" : [2, "before/after/both"]

[lo1tuma]

Seems like this is only related to keywords after a block statement. I think a rule like space-after-blocks (similar to space-before-blocks) would make more sense and should be easier to implement.

[lo1tuma]

@gcochard The config should also accept "always" and "never" for each option.

[michaelficarra]

While the try body is represented by a BlockStatement in the SpiderMonkey AST, it is not a block (or a statement). I would avoid applying block rules to all instances of curly braces in the JS syntax.

[nzakas]

@lo1tuma I'm not sold. Having space-keywords with a configuration like:

space-keywords: [2, {
   after: ["if"],
   before: ["catch"]
}

Seems like it would both make sense from a user perspective and be pretty easy to implement.

[lo1tuma]

@nzakas Your suggested configuration doesn’t work because you have to specify "always" or "never" for each keyword. So it would look like this:

"space-keywords": [2, {
    "after": {
        "if": "always",
        "else": "never"
    },
    "before": {
        "if": "never",
        "else": "always"
    }
}

I don’t like such complicated configurations.

@michaelficarra: Thanks, good to know. Maybe brace-style would be the correct rule.

[nzakas]

I don't think always/never is necessary. The ones you list should have spaces and the ones you don't shouldn't.

[lo1tuma]

We have an edge case with the function keyword where the default should be "don’t care" instead of "always" or "never".

[nzakas]

Yeah, function is weird. I'm wondering if that should be handled by space-function-name instead, to encapsulate all spacing related to function.

[atomantic]

+1 on this

[nzakas]

Thanks, +1s don't actually change anything. This issue is marked as accepted, which means it will get done when someone claims it.

[ilyavolodin]

If we want to remove space-after-keywords and replace it with space-keywords this issue should be marked as required for 1.0.0, since we want to avoid removing existing rules after 1.0.0

[nzakas]

Or we just add space-before-keywords. We need to be careful about adding more things into the 1.0.0 milestone or we might never get there.

I'd say if someone wants to drive this starting now, fine, but if it sits, then it will be post 1.0.0

[mmrko]

+1

[IanVS]

@mmrko, would you like to make an attempt at a solution? If the rule is important to you, the best way to get it implemented is to jump in and try it out. :)

[mmrko]

Okay, I'll take a stab at this :)

[mmrko]

Related PR: #3576