# Scope

Scope provides Inversion of Control using the dependency injection (DI) pattern for Dart applications.

Scope allows you to inject values into a scope and then 'use' those dependencies from any method (or constructor) called within that scope.

Scope provides DI for your call stack.

This is most easily understood via an example:

```dart
import 'package:scope/scope.dart';

/// create a key to access a scoped value
final ageKey = ScopeKey<int>();

void main() {
    /// create a Scope
    Scope()
    
    /// inject a value
    ..value<int>(ageKey, 18)
    
    /// run some code within the Scope
    ..run(() => a();
}
void a() => b();

/// `use` the injected value by its key 'ageKey'
void b() => print('You are ${use(ageKey)} years old');
```

We create a Scope within main and call the method `a()`  which calls `b()`. Both a() and b() are within the declared scope and therefore have access to the injected value `ageKey`.&#x20;

To access an injected value you call the `use` method.

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