> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/eslint/eslint/llms.txt
> Use this file to discover all available pages before exploring further.

# indent

> Enforce consistent indentation

# indent

Enforce consistent indentation throughout your code.

<Note>
  **Rule Type:** Layout\
  **Fixable:** Yes (automatically fixable)\
  **Deprecated:** Consider using Prettier
</Note>

## Rule Details

This rule enforces a consistent indentation style. The default is 4 spaces.

## Options

The first option is the indent size:

* Number (e.g., `2`, `4`) - Number of spaces
* `"tab"` - Use tab character

```js theme={null}
// 2 spaces
{
  "indent": ["error", 2]
}

// 4 spaces (default)
{
  "indent": ["error", 4]
}

// Tabs
{
  "indent": ["error", "tab"]
}
```

## Examples

### Incorrect (default 4 spaces)

```js theme={null}
if (a) {
  b=c;
  function foo(d) {
    e=f;
  }
}
```

### Correct (default 4 spaces)

```js theme={null}
if (a) {
    b=c;
    function foo(d) {
        e=f;
    }
}
```

## Advanced Options

The second parameter is an object with many options:

### `SwitchCase`

**Default:** `0`

Indent level for `case` clauses:

```js theme={null}
// With { "SwitchCase": 1 } and 2 spaces
switch(a){
  case "a":
    break;
  case "b":
    break;
}
```

### `VariableDeclarator`

**Default:** `1`

Indent level for multi-line variable declarations:

```js theme={null}
// With { "VariableDeclarator": 1 } and 2 spaces
var a,
  b,
  c;
```

### `MemberExpression`

**Default:** `1`

Indent level for multi-line property chains:

```js theme={null}
// With { "MemberExpression": 1 } and 2 spaces
foo
  .bar
  .baz();
```

### `FunctionDeclaration`

Configure function declaration indentation:

```js theme={null}
{
  "indent": ["error", 2, {
    "FunctionDeclaration": {
      "parameters": 1,
      "body": 1
    }
  }]
}
```

### `CallExpression`

Configure function call indentation:

```js theme={null}
{
  "indent": ["error", 2, {
    "CallExpression": {
      "arguments": 1
    }
  }]
}
```

### `ignoredNodes`

Array of selectors to ignore:

```js theme={null}
{
  "indent": ["error", 2, {
    "ignoredNodes": ["ConditionalExpression"]
  }]
}
```

## Configuration Examples

```js theme={null}
// 2 spaces
{
  "rules": {
    "indent": ["error", 2]
  }
}

// 4 spaces  
{
  "rules": {
    "indent": ["error", 4]
  }
}

// Tabs
{
  "rules": {
    "indent": ["error", "tab"]
  }
}

// 2 spaces with switch case indent
{
  "rules": {
    "indent": ["error", 2, { 
      "SwitchCase": 1 
    }]
  }
}

// Complex configuration
{
  "rules": {
    "indent": ["error", 2, {
      "SwitchCase": 1,
      "VariableDeclarator": 1,
      "MemberExpression": 1,
      "FunctionDeclaration": {
        "parameters": 1,
        "body": 1
      },
      "CallExpression": {
        "arguments": 1
      }
    }]
  }
}
```

## Common Patterns

### Switch Statements

```js theme={null}
// Without SwitchCase: 1
switch (a) {
case 1:
    break;
}

// With SwitchCase: 1 and 2 spaces
switch (a) {
  case 1:
    break;
}
```

### Chained Methods

```js theme={null}
// With MemberExpression: 1 and 2 spaces
chain
  .filter(x => x > 0)
  .map(x => x * 2)
  .forEach(console.log);
```

### Multi-line Variables

```js theme={null}
// With VariableDeclarator: 2 and 2 spaces
var a,
    b,
    c;
```

## When Not to Use It

<Tip>
  Most modern projects use Prettier for formatting. If you use Prettier, disable this rule.
</Tip>

Disable if:

* You use Prettier or another formatter
* You don't want to enforce indentation
* Your team hasn't agreed on indentation style

## Related Rules

* [indent-legacy](/rules/indent-legacy)