switch-case-braces.md

switch-case-braces

📝 Enforce consistent brace style for case clauses.

💼🚫 This rule is enabled in the ✅ recommended config. This rule is disabled in the ☑️ unopinionated config.

🔧 This rule is automatically fixable by the --fix CLI option.

1. Forbid braces for empty clauses.
2. Enforce braces for non-empty clauses.

Braces give each non-empty case its own explicit scope and keep case-body structure consistent.

Cases with lexical declarations that are used outside the case are reported without a fix, because adding braces would hide the bindings from the other cases.

Examples

// ❌
switch (foo) {
	case 1: {
	}
	case 2: {
		doSomething();
		break;
	}
}

// ✅
switch (foo) {
	case 1:
	case 2: {
		doSomething();
		break;
	}
}

// ❌
switch (foo) {
	case 1:
		doSomething();
		break;
}

// ✅
switch (foo) {
	case 1: {
		doSomething();
		break;
	}
}

Options

Type: string
Default: 'always'

• 'always' (default)
  • Require braces for non-empty clauses, and forbid braces for empty clauses.
• 'avoid'
  • Only allow braces when the block contains a top-level declaration.
• 'single-statement'
  • Require each case clause to have a single statement. Multiple statements must be wrapped in a block. A block with one statement is allowed only when that statement needs its own scope.

The following cases are considered valid:

/* eslint unicorn/switch-case-braces: ["error", "avoid"] */
switch (foo) {
	case 1:
		doSomething();
		break;
}

/* eslint unicorn/switch-case-braces: ["error", "avoid"] */
switch (foo) {
	case 1: {
		const bar = 2;
		doSomething(bar);
		break;
	}
}

The following case is considered invalid:

/* eslint unicorn/switch-case-braces: ["error", "avoid"] */
switch (foo) {
	case 1: {
		doSomething();
		break;
	}
}

The following cases are considered valid:

/* eslint unicorn/switch-case-braces: ["error", "single-statement"] */
function unicorn(foo) {
	switch (foo) {
		case 1:
			return foo;
		case 2: {
			doSomething();
			break;
		}
		case 3: {
			const bar = 2;
		}
	}
}

The following cases are considered invalid:

/* eslint unicorn/switch-case-braces: ["error", "single-statement"] */
function unicorn(foo) {
	switch (foo) {
		case 1:
			doSomething();
			break;
		case 2: {
			return foo;
		}
	}
}