@loopback/context/dist/context-observer.d.ts

Facilities to manage artifacts and their dependencies in your Node.js applications. The module exposes TypeScript/JavaScript APIs and decorators to register artifacts, declare dependencies, and resolve artifacts by keys. It also serves as an IoC container

import { Binding } from './binding';
import { BindingFilter } from './binding-filter';
import { Context } from './context';
import { ValueOrPromise } from './value-promise';
/**
 * Context event types. We support `bind` and `unbind` for now but
 * keep it open for new types
 */
export type ContextEventType = 'bind' | 'unbind' | string;
/**
 * Listen on `bind`, `unbind`, or other events
 * @param eventType - Context event type
 * @param binding - The binding as event source
 * @param context - Context object for the binding event
 */
export type ContextObserverFn = (eventType: ContextEventType, binding: Readonly<Binding<unknown>>, context: Context) => ValueOrPromise<void>;
/**
 * Observers of context bind/unbind events
 */
export interface ContextObserver {
    /**
     * An optional filter function to match bindings. If not present, the listener
     * will be notified of all binding events.
     */
    filter?: BindingFilter;
    /**
     * Listen on `bind`, `unbind`, or other events
     * @param eventType - Context event type
     * @param binding - The binding as event source
     */
    observe: ContextObserverFn;
}
/**
 * Context event observer type - An instance of `ContextObserver` or a function
 */
export type ContextEventObserver = ContextObserver | ContextObserverFn;