# Dom.InternalPropsHelpers

Helpers available while constructing component-owned host props.

## Signatures

```ts
export interface InternalPropsHelpers<Options> {
    readonly property: <const Key extends PropertyKey, const Fallback>(key: Key, fallback: Fallback) => NonNullish<Property<Options, Key>> | Fallback;
}
```

## Why

Internal defaults can read generic options while retaining exact non-nullish
output types.

## Ownership and lifetime

Helpers retain only the options object during synchronous prop construction.

## Property: property

Reads an option and substitutes `fallback` only for `null` or `undefined`.