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url: /api/renderers/web-components/src/interfaces/RegisterContext.md
---
[pantoken-root](../../../../index.md) / [renderers/web-components/src](../index.md) / RegisterContext

# Interface: RegisterContext

Alpha

The shared state a `register()` call builds once and threads to every [ElementDefinition](ElementDefinition.md).
It carries the prefix-aware registry adapter, the `tag()` helper for nested markup, the CSS-class
prefix `I`, the Invoker Commands support flag + router, the `wrapper`/`variantClass`/`iconSvg`
factories, and locale data (`strings`, `locale`, `dir`, `firstDay`).

## Properties

### registry

> **registry**: [`ElementRegistry`](ElementRegistry.md)

Alpha

The scoped registry: rewrites `instui-<base>` → the active-prefix tag on `get`/`define`.

***

### tag

> **tag**: (`base`) => `string`

Alpha

Map a base name to the active-prefix tag (for nested markup, `querySelector`, `tagName`).

#### Parameters

##### base

`string`

#### Returns

`string`

***

### I

> **I**: `object`

Alpha

The CSS-class prefix for the inlined component sheets — always `instui`, separate from the tag prefix.

#### prefix

> `readonly` **prefix**: `"instui"`

***

### invokerSupported

> **invokerSupported**: `boolean`

Alpha

Whether the browser supports the Invoker Commands API (`command`/`commandfor`).

***

### onCommand

> **onCommand**: `OnCommand`

Alpha

Route a target's `command` events (or a click fallback) to a handler.

***

### wrapper

> **wrapper**: (`tag`, `css`, `render`, `options?`) => `void`

Alpha

Define a shadow-DOM element: `<style>:host{display}css</style>` + markup from `render(host)`.
`invoker: true` forwards the host's `popovertarget`/`command` to the inner `<button>` (IDL).

#### Parameters

##### tag

`string`

##### css

`string`

##### render

(`host`) => `string`

##### options?

###### display?

`string`

###### invoker?

`boolean`

#### Returns

`void`

***

### variantClass

> **variantClass**: (`name`, `host`) => `string`

Alpha

Build a `.instui-<name>` class with an optional `-color-<variant>` modifier from `variant`.

#### Parameters

##### name

`string`

##### host

`HTMLElement`

#### Returns

`string`

***

### iconSvg

> **iconSvg**: (`name`) => `string`

Alpha

Resolve an icon name to inline SVG (empty string when unknown).

#### Parameters

##### name

`string`

#### Returns

`string`

***

### locale

> **locale**: `string`

Alpha

BCP47 locale tag used for `toLocaleDateString` and `Intl` formatting.

***

### dir

> **dir**: `"ltr"` | `"rtl"`

Alpha

Text direction derived from the active locale bundle.

***

### firstDay

> **firstDay**: `number`

Alpha

First day of week as JS `Date.getDay()` index (0=Sunday … 6=Saturday).

***

### strings

> **strings**: [`WebComponentStrings`](WebComponentStrings.md)

Alpha

Translated UI strings for all behavioral elements.