reactant-di/dist/esm/decorators/optional.js

A dependency injection lib for Reactant

import 'reflect-metadata';
import { decorate, optional as optional$1 } from 'inversify';
import { inject } from './inject.js';
import { METADATA_KEY } from '../constants.js';
import { setMetadata } from '../util.js';

/**
 * ## Description
 *
 * You can use `@optional()` to decorate an optionally injected module.
 *
 * If other modules have no relevant dependency injection or are also optionally injected, the module will not be injected by default unless the injected module is imported in the `modules` parameter.
 *
 * ## Example
 *
 * ```ts
 * @injectable()
 * class Bar {
 *   getValue() {
 *     return 'bar';
 *   }
 * }
 *
 * @injectable()
 * class Foo {
 *   getValue() {
 *     return 'foo';
 *   }
 * }
 *
 * @injectable()
 * class FooBar {
 *   constructor(@optional() public bar: Bar, @optional('foo') public foo: Foo) {}
 * }
 *
 * const fooBar = testBed({
 *   modules: [
 *    { provide: 'foo', useClass: Foo },
 *   ],
 *   main: FooBar,
 * });
 *
 * expect(fooBar.instance.foo.getValue()).toBe('foo');
 * expect(fooBar.fooBar.bar).toBeUndefined();
 * ```
 */
function optional(serviceIdentifier) {
    return function (target, key, index) {
        var paramtypes = Reflect.getMetadata(METADATA_KEY.paramtypes, target);
        setMetadata(METADATA_KEY.optional, paramtypes[index], serviceIdentifier);
        decorate(inject(serviceIdentifier), target, index);
        decorate(optional$1(), target, index);
    };
}

export { optional };