---
title: blank-line
description: Require blank lines between statements, class members, and switch cases.
---

- Rule ID: `tai-kun/blank-line`
- Auto-fix: Yes

Requires one blank line between statements, class members, and non-empty `switch` cases. This rule consolidates six former rules (`blank-line-after-control-block`, `blank-line-after-declaration`, `blank-line-after-variable-declaration`, `blank-line-before-return`, `blank-line-between-class-members`, and `blank-line-between-switch-cases`), each of which can be toggled with an option. Each boundary produces at most one diagnostic, so the items never contradict each other.

## Configuration [#configuration]

Add the rule to `lint.rules` in `vite.config.ts` to enable it. All options default to `true`.

```ts
"tai-kun/blank-line": ["error", {
  afterControlBlock: true,
  afterDeclaration: true,
  afterVariableDeclaration: true,
  beforeReturn: true,
  betweenClassMembers: true,
  betweenSwitchCases: true,
  betweenTypeMembers: true,
}],
```

| Option                     | Description                                                                                                                      |
| -------------------------- | -------------------------------------------------------------------------------------------------------------------------------- |
| `afterControlBlock`        | Require a blank line after `if`, `for`, `while`, `switch`, `try`, and similar blocks when another statement follows.             |
| `afterDeclaration`         | Require a blank line after function, class, `interface`, `type`, and similar declarations when another statement follows.        |
| `afterVariableDeclaration` | Require a blank line after a variable declaration group when another statement follows, and remove blank lines inside the group. |
| `beforeReturn`             | Require a blank line before a `return` statement when another statement precedes it.                                             |
| `betweenClassMembers`      | Require a blank line between class members.                                                                                      |
| `betweenSwitchCases`       | Require a blank line between non-empty cases.                                                                                    |
| `betweenTypeMembers`       | Require a blank line above JSDoc comments between `interface` and type literal members.                                          |

## Examples [#examples]

### Invalid [#invalid]

```ts
const ready = getItems();
ready.sort(compareNames);
const sorted = [];
```

### Valid [#valid]

```ts
const ready = getItems();
ready.sort(compareNames);

const sorted = [];
```

## Notes [#notes]

- Expression statements that use the declared variables, such as `ready.sort(compareNames)`, belong to the same group, and blank lines between them are removed.
- Consecutive variable declarations are treated as one group, with or without blank lines between them.
- Overload signatures, getter/setter pairs, and empty fallthrough cases are excluded.
- Blank lines around intervening line comments (`//`) and plain block comments (`/* */`) are optional.
- A blank line is required above JSDoc-style block comments (starting with `/**`).
- Extra blank lines are collapsed to one by Oxfmt.

## Related rules [#related-rules]

- [`overload-signatures-adjacent`](/vp-lint-plugins/en/rules/overload-signatures-adjacent)
- [`member-ordering`](/vp-lint-plugins/en/rules/member-ordering)