# HostComponentInfo

**Kind:** Interface

**Source:** [`packages/core/injector/instance-wrapper.ts`](https://github.com/nestjs/nest/blob/master/packages/core/injector/instance-wrapper.ts#L25)

**Part of:** [Core](subsystem-packages-core)

`HostComponentInfo` describes metadata associated with the component that hosts a provider or dependency instance. It identifies the host through its injection `token` and indicates whether the host belongs to a durable dependency tree via `isTreeDurable`.

## Properties

| Property | Type |
|---|---|
| `token` | `InjectionToken` |
| `isTreeDurable` | `boolean` |

## Diagram

```mermaid
graph LR
  Wrapper[Instance Wrapper] --> HostInfo[HostComponentInfo]
  HostInfo --> Token[token: InjectionToken]
  HostInfo --> Durable[isTreeDurable: boolean]
  Token --> HostComponent[Host Component / Provider]
  Durable --> Tree[Dependency Tree Durability]
```

## Usage

```ts
import type { InjectionToken } from '@nestjs/common';
import type { HostComponentInfo } from '@nestjs/core/injector/instance-wrapper';

class UsersService {}

const hostComponentInfo: HostComponentInfo = {
  token: UsersService as InjectionToken,
  isTreeDurable: true,
};

// Store this metadata when creating or inspecting an instance wrapper.
function registerHost(info: HostComponentInfo) {
  console.log(`Host token: ${String(info.token)}`);
  console.log(`Tree durable: ${info.isTreeDurable}`);
}

registerHost(hostComponentInfo);
```

## AI Coding Instructions

- Preserve both fields when cloning, transforming, or forwarding host component metadata.
- Use the same injection token that identifies the owning provider or component; do not substitute an instance value.
- Set `isTreeDurable` based on dependency-tree durability rules, especially when working with scoped providers.
- Treat `token` as an `InjectionToken`, which may be a class, string, symbol, or custom token.
- Keep this interface focused on host metadata; lifecycle and instance state belong on the surrounding instance wrapper.

## Used by

2 references from 2 files. Each is a place in this repository where the symbol is actually used — go read one rather than trusting an example.

### Imported by (2)

- `DurableContextIdStrategy` — `integration/inspector/src/durable/durable-context-id.strategy.ts`:6
- `TenantContext` — `integration/scopes/src/durable/durable-context-id.strategy.ts`:4