# `InvoiceNumber`

An invoice's number: up to 200 characters, as your own system writes it.

Use it for the number on an invoice, such as `INV-2026-0042`. For what a bank payment says, use [`PaymentReference`](/docs/types/type-payment-reference.md).

## Shape

One value, held as text in one set form, with no parts: `2026/17`.

## Example

```jadpo
InvoiceNumber("INV-2026-0042")
```

`InvoiceNumber(raw)` checks the text, and text that isn't one breaks the `format` rule.

`text.parse(raw, as: InvoiceNumber)` reads one from text that comes from outside. Text that isn't one at all fails `malformed`, such as ` INV-1` or `INV-1 `.

## Good to know

- It can't start or end with a space, or hold line breaks.
- `==` tells you whether two are the same. `<` and `list.sort_by` don't take it.

## In JSON

A string, in a request, a response or `json.write`:

```json
"INV-2026-0042"
"2026/17"
```

## Details

<details>
<summary>Text form, storage, how it is shown, and operations</summary>

`InvoiceNumber` is in the group Money and banking, and has been in Jadpo since 0.1.0.

### Text form

`text.from` writes one standard text form, the same form `text.parse` reads back: `INV-2026-0042` and `2026/17`.

### How it is stored

It is stored in one column named for the field, of type `text`. `2026/17` is stored as `'2026/17'`.

### How it is shown to people

`text.format(value, locale:)` shows it to people in their locale.

With `locale: Locale.en_gb`:

| Value | Shown |
|---|---|
| `INV-2026-0042` | `INV-2026-0042` |
| `2026/17` | `2026/17` |

### Operations

It also takes `text.parse`, `text.from`, `text.format`, `json.read`, `json.write` and `==`. [How every standard type behaves](/docs/every-standard-type-meets-one-contract.md) says how they work.

</details>