# asEnvironmentPlaceholder

- Module: [Aspire.Hosting.Docker](/reference/api/typescript/aspire.hosting.docker.md)
- Version: `13.3.0`
- Kind: `method`
- Source: [GitHub](https://github.com/microsoft/aspire)

Creates a Docker Compose environment variable placeholder from a parameter builder

## Definition

```typescript
interface ParameterResource {
  // ... omitted for brevity
  asEnvironmentPlaceholder(dockerComposeService: DockerComposeServiceResource): string
}
```

## Parameters

- `dockerComposeService` ([DockerComposeServiceResource](/reference/api/typescript/aspire.hosting.docker/dockercomposeserviceresource.md))

## Returns

`string`

## Applies to

- [ParameterResource](/reference/api/typescript/aspire.hosting.docker/parameterresource.md)