@provide

The @provide decorator injects providers into the class field as a “singleton”, meaning the same instance is shared across all injections. This allows you to inject the provider wherever needed, without having to worry about creating multiple instances.

You can customize this behavior using scope-modifier decorators, such as @transient and @isolated, which allow more granular control over the lifecycle and scope of injected instances. These will be covered in a later section.

Example

import { application, provide, provider } from 'aspectra'
 
@provider
export class Database {
  private constructor() {
    console.log(`I'm only called once!`)
  }
 
  public getAll() {
    return ['item1', 'item2']
  }
}
 
@application
class Application {
  @provide(Database)
  private readonly database!: Database
 
  @provide(Database)
  private readonly other!: Database // same instance as `database`
 
  public start() {
    console.log(this.database.getAll())
  }
}

[auto-generated] output:

I'm only called once!
[ 'item1', 'item2' ]