Enforce spacing around colons of switch statements (switch-colon-spacing)

The --fix option on the command line can automatically fix some of the problems reported by this rule.

Spacing around colons improves readability of case/default clauses.

Rule Details

This rule controls spacing around colons of case and default clauses in switch statements. This rule does the check only if the consecutive tokens exist on the same line.

This rule has 2 options that are boolean value.

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

• "after": true (Default) … requires one or more spaces after colons.
• "after": false … disallows spaces after colons.
• "before": true … requires one or more spaces before colons.
• "before": false (Default) … disallows before colons.

Examples of incorrect code for this rule:

/*eslint switch-colon-spacing: "error"*/

switch (a) {
    case 0 :break;
    default :foo();
}

Examples of correct code for this rule:

/*eslint switch-colon-spacing: "error"*/

switch (a) {
    case 0: foo(); break;
    case 1:
        bar();
        break;
    default:
        baz();
        break;
}

Examples of incorrect code for this rule with {"after": false, "before": true} option:

/*eslint switch-colon-spacing: ["error", {"after": false, "before": true}]*/

switch (a) {
    case 0: break;
    default: foo();
}

Examples of correct code for this rule with {"after": false, "before": true} option:

/*eslint switch-colon-spacing: ["error", {"after": false, "before": true}]*/

switch (a) {
    case 0 :foo(); break;
    case 1 :
        bar();
        break;
    default :
        baz();
        break;
}

When Not To Use It

If you don’t want to notify spacing around colons of switch statements, then it’s safe to disable this rule.

Version

This rule was introduced in ESLint 4.0.0-beta.0.

Resources

• Rule source
• Documentation source