# Loading

Represents active work that has not produced a prior value or failure.

## Signatures

```ts
export interface Loading {
    readonly _tag: "Loading";
    readonly progress?: Progress | undefined;
}
```

## Why

Loading is separate from refreshing so consumers can decide whether stale content remains available.

## Ownership and lifetime

This plain object acquires no resources; the operation it describes is owned elsewhere and the object is not frozen.

## Property: _tag

The discriminant for loading without a prior result.

## Property: _tag: Why

The literal tag makes loading branches explicit and exhaustively checkable.

## Property: _tag: Ownership and lifetime

Inherits the resource-free lifetime of its enclosing state.

## Property: progress

Optional progress reported by the active producer.

## Property: progress: Why

Keeping progress optional supports both determinate and uninstrumented operations.

## Property: progress: Ownership and lifetime

Inherits the resource-free lifetime of its enclosing state.

## Examples

```ts
import { loading } from "@typed/async-data"
const state = loading({ loaded: 0 })
```