Binding

A binding connects an identifier to a dependency item. The injector uses bindings to know what to provide when a dependency is requested.

Registering Bindings

In the Constructor

The most common way is to pass bindings when creating the injector:


const injector = new Injector([
  [AuthService],                              // Class as both identifier and item
  [ILogger, { useClass: ConsoleLogger }],     // Interface → Class
  [IConfig, { useValue: { debug: true } }],   // Interface → Value
  [IFactory, { useFactory: () => create() }], // Interface → Factory
]);

Using the `add` Method

You can also add bindings later:


const injector = new Injector();
 
injector.add([AuthService]);
injector.add([ILogger, { useClass: ConsoleLogger }]);

Be careful with add — make sure bindings are registered before they are requested, or you’ll get an error.

Modifying Bindings

Replace a Binding


injector.replace([ILogger, { useClass: FileLogger }]);

Delete a Binding


injector.delete(ILogger);

You can only replace or delete bindings before they are resolved. Once a dependency has been created, changes won’t take effect.