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Switch Case Blocks

Enforce block-wrapped switch cases so each branch is self-contained and declarations never leak across cases.

Summary​

The switch-case-blocks rule requires every non-empty switch case to wrap its body in a block ({ }). Empty cases used for intentional fallthrough are allowed.

Why Use This Rule?​

  1. Prevents accidental variable leaks between cases that share the same function scope.
  2. Makes each case self-contained so reordering or removing one won't break another.
  3. Gives a consistent visual boundary that's easier to scan.

Examples​

switch (action) {
  case 'start': {
    const id = getId();
    run(id);
    break;
  }

  case 'stop': {
    cleanup();
    break;
  }

  // Empty cases for intentional fallthrough are fine.
  case 'pause':
  case 'resume':
  default: {
    log('unhandled action');
    break;
  }
}

Configuration​

Enable the rule in your ESLint flat config:

import { switchCaseBlocks } from '@cbnventures/nova/rules/eslint';

export default [
  {
    plugins: {
      '@cbnventures/nova': {
        rules: {
          'switch-case-blocks': switchCaseBlocks,
        },
      },
    },
    rules: {
      '@cbnventures/nova/switch-case-blocks': ['error'],
    },
  },
];

This rule has no additional options.

Troubleshooting​

  • False positive on an empty case. — Empty cases (no statements at all) are allowed for intentional fallthrough. If the case has any statement, it needs a block.
  • Conflicts with another formatter. — Some formatters strip braces from single-statement cases. Configure the formatter to preserve block statements inside switch cases.