# FlexBox

> Flexbox layout primitive for stacks and rows.

- Status: beta
- Group: layout
- Page: https://www.digitaltableteur.com/design-system/components/flex-box
- Contract: https://www.digitaltableteur.com/contracts/v1/FlexBox.contract.json

## When to use

FlexBox is the free-form single-axis primitive: every flexbox knob exposed as a prop, emitted as inline style; deliberately css-less. Numbers become px gaps; strings pass through, so prefer space tokens ("var(--space-internal-16)"). Use it for one-off arrangements where Stack's token scale is too coarse; when you just need vertical rhythm, Stack is the sharper tool.

## When not to use

- Do not rebuild Grid with wrap and width math; two-dimensional layouts belong to Grid.
- Do not hardcode magic px strings when a space token exists; the rhythm gate will flag it.

## Look-alikes

The contract names no look-alike with a deciding condition.

## Props

| Prop | Type | Default | Description | Required |
| --- | --- | --- | --- | --- |
| `direction` | `"row" \| "row-reverse" \| "column" \| "column-reverse"` | `row` | Flex-direction. | No |
| `wrap` | `"nowrap" \| "wrap" \| "wrap-reverse"` | `nowrap` | Flex-wrap. | No |
| `justify` | `"center" \| "flex-start" \| "flex-end" \| "space-between" \| "space-around" \| "space-evenly"` | `flex-start` | Main-axis distribution. | No |
| `align` | `"center" \| "flex-start" \| "flex-end" \| "stretch" \| "baseline"` | `stretch` | Cross-axis item alignment. | No |
| `alignContent` | `"center" \| "flex-start" \| "flex-end" \| "space-between" \| "space-around" \| "stretch"` | none | Cross-axis line distribution when wrapping. | No |
| `gap` | `string \| number` | none | Shorthand gap (CSS length or number of px). | No |
| `rowGap` | `string \| number` | none | Row gap override. | No |
| `columnGap` | `string \| number` | none | Column gap override. | No |
| `style` | `React.CSSProperties` | none | Inline style overrides applied after generated flex declarations. | No |
| `children` | `React.ReactNode` | none | Flex items rendered inside the container. | Yes |

## Variants

- Allowed `align` values: `center`, `flex-start`, `flex-end`, `stretch`, `baseline` (default `stretch`).
- Allowed `direction` values: `row`, `row-reverse`, `column`, `column-reverse` (default `row`).
- Allowed `wrap` values: `nowrap`, `wrap`, `wrap-reverse` (default `nowrap`).
- Allowed `justify` values: `center`, `flex-start`, `flex-end`, `space-between`, `space-around`, `space-evenly` (default `flex-start`).
- Allowed `alignContent` values: `center`, `flex-start`, `flex-end`, `space-between`, `space-around`, `stretch`.

## Invalid combinations

The contract records no invalid combinations.

## Keyboard

The contract records no keyboard interaction.

## Rules

Every item under When not to use is a MUST NOT. MUST and SHOULD follow RFC 2119.

| Level | Rule | How it is checked |
| --- | --- | --- |
| MUST | Required stories produce no axe violations at the configured severity. | Automated by `npm run test:stories:matrix:ci`. WCAG 2.5.8. |
| MUST | The accessibility tree (role, name, state) matches the committed snapshot for every required story. | Automated by `npm run test:stories:matrix:ci`. WCAG 1.3.1, 4.1.2. |
| MUST | The component remains legible and operable under a real browser forced-colors: active pass. | Automated by `npm run test:stories:hc`. |
| MUST | A human completed an end-to-end accessibility review of this component. | Manual review, last on 2026-05-28. |
| SHOULD | Prefer Stack for standard token-gapped rows/columns; FlexBox is for the layouts Stack cannot express. | Not stated in the contract. |
| SHOULD | Pass string gaps as space tokens; numeric gaps are raw px and should stay rare. | Not stated in the contract. |
| SHOULD | Use align="center" for mixed-height inline clusters (icon + text + badge). | Not stated in the contract. |
| SHOULD | Lean on the div passthrough for aria roles when the flex row is semantically a group. | Not stated in the contract. |
| SHOULD NOT | Do not rebuild Grid with wrap and width math; two-dimensional layouts belong to Grid. | Not stated in the contract. |
| SHOULD NOT | Do not hardcode magic px strings when a space token exists; the rhythm gate will flag it. | Not stated in the contract. |

## Install and import

- Install: `npm install @digitaltableteur/react` (version 0.9.1, restricted access on npm).
- Import: `import { FlexBox } from "@digitaltableteur/react";`
- Entry point: `@digitaltableteur/react/layout` exports it too.
- Styles: import `@digitaltableteur/react/style.css` once at the app boundary.
- Also available as the custom element `<dt-flex-box>`; see the custom elements manifest.

## Links

- Machine-readable contract (Design System Contract 1.0): https://www.digitaltableteur.com/contracts/v1/FlexBox.contract.json
- Markdown version of this page: https://www.digitaltableteur.com/design-system/components/flex-box.md
- Component index as JSON: https://www.digitaltableteur.com/design-system/components.json
- All components: https://www.digitaltableteur.com/design-system/components
- Source: The implementation lives in a private repository. This page, its Markdown twin and the contract are generated from it at build time and are the public source of truth.