Disallow space before colon in SwitchStatement

Hi guys! Today there is no way to disallow space before colon in switch-case statement:

switch (foo) {
  case 'bar' : 
    return '^---oh, that space...';
}

I already use keyword-spacing, but I can’t configure it for my case. I tried key-spacing too, but it still doesn’t work. My configuration looks like this:

    ...
    "key-spacing": "error",
    "keyword-spacing": "error",
    ...

You can also reproduce this by http://eslint.org/demo/ with enabled keyword-spacing & key-spacing.

I’ve asked about this in gitter and I was recommended to create an issue. I don’t know, should it be a new rule or modification of an existing?

Thank you!

[mysticatea]

I’ll champion, too. I try to make a concrete proposal.

label-colon-spacing (or label-spacing)

This rule enforce usage of spaces before/after the colon of labels. The labels is both LabeledStatement and SwitchCase nodes’.

A_LABEL : while (true) foo();
//     ^ ^

switch (a) {
    case A : foo(); break;
    //    ^ ^
    case B :
    //    ^ (if there is a line terminator after the colon, this rule does nothing for spacing after the colon.)
    default : foo(); break;
    //     ^ ^
}

Options

{
    "label-colon-spacing": ["error", {"after": true, "before": false}]
}

• after
  • true (default) requires spaces after the colon of labels.
  • false disallows spaces after the colon of labels.
• before
  • true requires spaces before the colon of labels.
  • false (default) disallows spaces before the colon of labels.

Examples

👎 incorrect code for this rule with the default {"after": true, "before": false} option.

A_LABEL :foo();

switch (a) {
    case A :foo();
    default :foo();
}

👍 correct code for this rule with the default {"after": true, "before": false} option.

A_LABEL: foo();

switch (a) {
    case A: foo();
    default: foo();
}

👎 incorrect code for this rule with the {"after": false, "before": true} option.

A_LABEL: foo();

switch (a) {
    case A: foo();
    default: foo();
}

👍 correct code for this rule with the default {"after": false, "before": true} option.

A_LABEL :foo();

switch (a) {
    case A :foo();
    default :foo();
}

[kaicataldo]

This has now been accepted! I support adding a rule for this, however it’s not entirely clear to me where we stand with the proposal. It looks like there were two votes for a rule that specifically checks switch cases.