# generaltranslation: General Translation Core SDK: formatListToParts
URL: https://generaltranslation.com/en-US/docs/core/class/methods/formatting/format-list-to-parts.mdx
---
title: formatListToParts
description: API reference for the formatListToParts method to format lists into parts while preserving original types
---

## Overview

The `formatListToParts` method formats an array into locale-specific parts, inserting string separators between items while preserving the original types of each element.
Unlike `formatList`, which returns a flat string, this method returns an `Array<T | string>` — making it ideal for mixed-type arrays containing strings, numbers, objects, or JSX elements.

```typescript
const gt = new GT({ locales: ['en'] });

const parts = gt.formatListToParts(['apple', 42, { type: 'fruit' }]);
// Returns: ['apple', ', ', 42, ', and ', { type: 'fruit' }]
```


## Reference

### Parameters

| Name | Type | Description |
|------|------|-------------|
| `array` | `Array<T>` | The array of items to format |
| `options?` | `ListFormatPartsOptions` | Optional formatting configuration |

### ListFormatPartsOptions

Extends `Intl.ListFormatOptions` with additional locale specification:

| Name | Type | Description |
|------|------|-------------|
| `locales?` | `string \| string[]` | Override locales for formatting (defaults to instance locales) |
| `type?` | `'conjunction' \| 'disjunction' \| 'unit'` | List formatting type (default: `'conjunction'`) |
| `style?` | `'long' \| 'short' \| 'narrow'` | List formatting style (default: `'long'`) |

### Returns

`Array<T | string>` - An array of the original items interleaved with locale-specific string separators.

---

## Examples

### Basic list formatting

```typescript copy
import { GT } from 'generaltranslation';

const gt = new GT({ locales: ['en'] });

// Conjunction (default) — "and" list
console.log(gt.formatListToParts(['A', 'B', 'C']));
// Output: ['A', ', ', 'B', ', and ', 'C']

// Disjunction — "or" list
console.log(gt.formatListToParts(['A', 'B', 'C'], { type: 'disjunction' }));
// Output: ['A', ', ', 'B', ', or ', 'C']
```

### Mixed-type arrays

```typescript copy
// Numbers and objects are preserved
console.log(gt.formatListToParts(['apple', 42, { type: 'fruit' }]));
// Output: ['apple', ', ', 42, ', and ', { type: 'fruit' }]
```

### Style variations

```typescript copy
// Short style
console.log(gt.formatListToParts(['first', 'second'], { style: 'short' }));
// Output: ['first', ' & ', 'second']

// Unit style
console.log(gt.formatListToParts(['1km', '2mi'], { type: 'unit' }));
// Output: ['1km', ', ', '2mi']
```

### Locale-specific formatting

```typescript copy
// Spanish disjunction
console.log(gt.formatListToParts(['red', 'green', 'blue'], {
  locales: ['es'],
  type: 'disjunction'
}));
// Output: ['red', ', ', 'green', ' o ', 'blue']
```

---

## Notes

* Original item types are preserved — only string separators are inserted between elements
* This is the key differentiator from `formatList`, which returns a flat `string`
* Particularly useful for rendering mixed-type arrays in UI frameworks like React
* The method uses browser-native `Intl.ListFormat` under the hood
* `type: 'conjunction'` produces "and" lists, `'disjunction'` produces "or" lists, and `'unit'` produces unit-style lists

## Next steps

* Check out [`Intl.ListFormat` documentation](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/ListFormat) for more options
* See [`format-num`](/docs/core/class/methods/formatting/format-num) for number formatting
* See standalone [`format-list-to-parts`](/docs/core/functions/formatting/format-list-to-parts) for use without GT instance
* See [`format-message`](/docs/core/class/methods/formatting/format-message) for message formatting with list interpolation