---
url: /matchers/to-have-underline.md
description: Assert that a terminal cell has underline styling with optional style check
---

# toHaveUnderline

::: warning Deprecated
Prefer [toHaveAttrs](/matchers/to-have-attrs) which checks multiple attributes at once:

```typescript
expect(term.cell(0, 0)).toHaveAttrs({ underline: true })
```

:::

Assert that a cell has underline styling. Optionally check for a specific underline style.

## Signature

```typescript
expect(cell).toHaveUnderline(style?: UnderlineStyle)
```

## Parameters

| Parameter | Type             | Description                      |
| --------- | ---------------- | -------------------------------- |
| `style`   | `UnderlineStyle` | Optional specific style to check |

`UnderlineStyle`: `"single"` | `"double"` | `"curly"` | `"dotted"` | `"dashed"`

## Usage

```typescript
// Any underline
expect(term.cell(0, 0)).toHaveUnderline()

// Specific underline style
expect(term.cell(0, 0)).toHaveUnderline("single")
expect(term.cell(0, 0)).toHaveUnderline("curly") // spell-check style
expect(term.cell(0, 0)).toHaveUnderline("double")
expect(term.cell(0, 0)).toHaveUnderline("dotted")
expect(term.cell(0, 0)).toHaveUnderline("dashed")

// Negation
expect(term.cell(0, 0)).not.toHaveUnderline()
```

## Accepts

| Region            | Supported |
| ----------------- | --------- |
| `term.cell(r, c)` | Yes       |
| `term.screen`     | No        |
| `term.row(n)`     | No        |

## Notes

* Without a `style` argument, matches any underline style
* Curly underline is commonly used for spell-check indicators
* Not all terminal backends support all underline styles

## See Also

* [toHaveAttrs](/matchers/to-have-attrs) - composable attribute matcher (preferred)
* [toBeBold](/matchers/to-be-bold) - bold styling
* [toBeItalic](/matchers/to-be-italic) - italic styling
* [toBeStrikethrough](/matchers/to-be-strikethrough) - strikethrough styling