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lang: en
title: 'API docs: context.inject.binding'
keywords: LoopBack 4.0, LoopBack 4, Node.js, TypeScript, OpenAPI
sidebar: lb4_sidebar
editurl: https://github.com/loopbackio/loopback-next/tree/master/packages/context
permalink: /doc/en/lb4/apidocs.context.inject.binding.html
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[Home](./index.md) > [@loopback/context](./context.md) > [inject](./context.inject.md) > [binding](./context.inject.binding.md)
## inject.binding variable
Inject the binding object for the given key. This is useful if a binding needs to be set up beyond just a constant value allowed by `@inject.setter`<!-- -->. The injected binding is found or created based on the `metadata.bindingCreation` option. See `BindingCreationPolicy` for more details.
<b>Signature:</b>
```typescript
binding: (bindingKey?: string | BindingKey<unknown> | undefined, metadata?: InjectBindingMetadata | undefined) => (target: Object, member: string | undefined, methodDescriptorOrParameterIndex?: number | TypedPropertyDescriptor<any> | undefined) => void
```
## Example
```ts
class MyAuthAction {
@inject.binding('current-user', {
bindingCreation: BindingCreationPolicy.ALWAYS_CREATE,
})
private userBinding: Binding<UserProfile>;
async authenticate() {
this.userBinding.toDynamicValue(() => {...});
}
}
```