reflective_injector.spec.ts

/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import 'reflect-metadata';

import {
  Inject,
  Injectable,
  InjectionToken,
  Injector,
  Optional,
  Provider,
  ReflectiveInjector,
  ReflectiveKey,
  Self,
  forwardRef,
} from '../src';
import { ReflectiveInjector_ } from '../src/di/reflective_injector';
import { ResolvedReflectiveProvider_ } from '../src/di/reflective_provider';
import { getOriginalError } from '../src/errors';
import { expect } from './matchers';
import { stringify } from '../src/util';

class Engine {}

class BrokenEngine {
  constructor() {
    throw new Error('Broken Engine');
  }
}

class DashboardSoftware {}

@Injectable()
class Dashboard {
  constructor(software: DashboardSoftware) {}
}

class TurboEngine extends Engine {}

@Injectable()
class Car {
  constructor(public engine: Engine) {}
}

@Injectable()
class CarWithOptionalEngine {
  constructor(@Optional() public engine: Engine) {}
}

@Injectable()
class CarWithDashboard {
  engine: Engine;
  dashboard: Dashboard;
  constructor(engine: Engine, dashboard: Dashboard) {
    this.engine = engine;
    this.dashboard = dashboard;
  }
}

@Injectable()
class SportsCar extends Car {}

@Injectable()
class CarWithInject {
  constructor(@Inject(TurboEngine) public engine: Engine) {}
}

@Injectable()
class CyclicEngine {
  constructor(car: Car) {}
}

class NoAnnotations {
  constructor(secretDependency: any) {}
}

function factoryFn(a: any) {}

const dynamicProviders = [
  { provide: 'provider0', useValue: 1 },
  { provide: 'provider1', useValue: 1 },
  { provide: 'provider2', useValue: 1 },
  { provide: 'provider3', useValue: 1 },
  { provide: 'provider4', useValue: 1 },
  { provide: 'provider5', useValue: 1 },
  { provide: 'provider6', useValue: 1 },
  { provide: 'provider7', useValue: 1 },
  { provide: 'provider8', useValue: 1 },
  { provide: 'provider9', useValue: 1 },
  { provide: 'provider10', useValue: 1 },
];

function createInjector(providers: Provider[], parent?: ReflectiveInjector | null): ReflectiveInjector_ {
  const resolvedProviders = ReflectiveInjector.resolve(providers.concat(dynamicProviders));
  if (parent != null) {
    return parent.createChildFromResolved(resolvedProviders) as ReflectiveInjector_;
  } else {
    return ReflectiveInjector.fromResolvedProviders(resolvedProviders) as ReflectiveInjector_;
  }
}

describe(`injector`, () => {
  it('should instantiate a class without dependencies', () => {
    const injector = createInjector([Engine]);
    const engine: Engine = injector.get(Engine);

    expect(engine).toBeAnInstanceOf(Engine);
  });

  it('should resolve dependencies based on type information', () => {
    const injector = createInjector([Engine, Car, CarWithOptionalEngine]);
    const car: Car = injector.get(Car);

    expect(car).toBeAnInstanceOf(Car);
    expect(car.engine).toBeAnInstanceOf(Engine);
  });

  it('should resolve dependencies based on @Inject annotation', () => {
    const injector = createInjector([TurboEngine, Engine, CarWithInject]);
    const car: CarWithInject = injector.get(CarWithInject);

    expect(car).toBeAnInstanceOf(CarWithInject);
    expect(car.engine).toBeAnInstanceOf(TurboEngine);
  });

  it('should throw when no type and not @Inject (class case)', () => {
    expect(() => createInjector([NoAnnotations])).toThrowError(
      "Cannot resolve all parameters for 'NoAnnotations'(?). " +
        'Make sure that all the parameters are decorated with Inject or have valid type annotations ' +
        "and that 'NoAnnotations' is decorated with Injectable."
    );
  });

  it('should throw when no type and not @Inject (factory case)', () => {
    expect(() => createInjector([{ provide: 'someToken', useFactory: factoryFn }])).toThrowError(
      "Cannot resolve all parameters for 'factoryFn'(?). " +
        'Make sure that all the parameters are decorated with Inject or have valid type annotations ' +
        "and that 'factoryFn' is decorated with Injectable."
    );
  });

  it('should cache instances', () => {
    const injector = createInjector([Engine]);

    const e1: Engine = injector.get(Engine);
    const e2: Engine = injector.get(Engine);

    expect(e1).toEqual(e2);
  });

  it('should provide to a value', () => {
    const injector = createInjector([{ provide: Engine, useValue: 'fake engine' }]);

    const engine: string = injector.get(Engine);
    expect(engine).toEqual('fake engine');
  });

  it('should inject dependencies instance of InjectionToken', () => {
    const TOKEN = new InjectionToken<string>('token');

    const injector = createInjector([
      { provide: TOKEN, useValue: 'by token' },
      { provide: Engine, useFactory: (dep: string) => dep, deps: [[TOKEN]] },
    ]);

    const engine: string = injector.get(Engine);
    expect(engine).toEqual('by token');
  });

  it('should provide to a factory', () => {
    function sportsCarFactory(engine: Engine) {
      return new SportsCar(engine);
    }

    const injector = createInjector([Engine, { provide: Car, useFactory: sportsCarFactory, deps: [Engine] }]);

    const car: SportsCar = injector.get(Car);
    expect(car).toBeAnInstanceOf(SportsCar);
    expect(car.engine).toBeAnInstanceOf(Engine);
  });

  it('should supporting provider to null', () => {
    const injector = createInjector([{ provide: Engine, useValue: null }]);
    const engine: null = injector.get(Engine);
    expect(engine).toBeNull();
  });

  it('should provide to an alias', () => {
    const injector = createInjector([Engine, SportsCar, { provide: Car, useExisting: SportsCar }]);

    const car: SportsCar = injector.get(Car);
    const sportsCar: SportsCar = injector.get(SportsCar);
    expect(car).toBeAnInstanceOf(SportsCar);
    expect(car).toBe(sportsCar);
    expect(sportsCar.engine).toBeAnInstanceOf(Engine);
  });

  it('should support multiProviders', () => {
    const injector = createInjector([
      Engine,
      { provide: Car, useClass: SportsCar, multi: true },
      { provide: Car, useClass: CarWithOptionalEngine, multi: true },
    ]);

    const cars: [SportsCar, CarWithOptionalEngine] = injector.get(Car);
    expect(cars.length).toEqual(2);
    expect(cars[0]).toBeAnInstanceOf(SportsCar);
    expect(cars[1]).toBeAnInstanceOf(CarWithOptionalEngine);
  });

  it('should support multiProviders that are created using useExisting', () => {
    const injector = createInjector([Engine, SportsCar, { provide: Car, useExisting: SportsCar, multi: true }]);

    const cars: [SportsCar] = injector.get(Car);
    expect(cars.length).toEqual(1);
    expect(cars[0]).toBe(injector.get(SportsCar));
  });

  it('should throw when the aliased provider does not exist', () => {
    const injector = createInjector([{ provide: 'car', useExisting: SportsCar }]);
    const e = `No provider for ${stringify(SportsCar)}! (car -> ${stringify(SportsCar)})`;
    expect(() => injector.get('car')).toThrowError(e);
  });

  it('should handle forwardRef in useExisting', () => {
    const injector = createInjector([
      { provide: 'originalEngine', useClass: forwardRef(() => Engine) },
      { provide: 'aliasedEngine', useExisting: forwardRef(() => 'originalEngine') as any },
    ]);
    expect(injector.get('aliasedEngine')).toBeAnInstanceOf(Engine);
  });

  it('should support overriding factory dependencies', () => {
    const injector = createInjector([
      Engine,
      { provide: Car, useFactory: (engine: Engine) => new SportsCar(engine), deps: [Engine] },
    ]);

    const car: SportsCar = injector.get(Car);
    expect(car).toBeAnInstanceOf(SportsCar);
    expect(car.engine).toBeAnInstanceOf(Engine);
  });

  it('should support optional dependencies', () => {
    const injector = createInjector([CarWithOptionalEngine]);

    const car: CarWithOptionalEngine = injector.get(CarWithOptionalEngine);
    expect(car).toBeAnInstanceOf(CarWithOptionalEngine);
    expect(car.engine).toEqual(null);
  });

  it('should flatten passed-in providers', () => {
    const injector = createInjector([[[Engine, Car]]]);

    const car: Car = injector.get(Car);
    expect(car).toBeAnInstanceOf(Car);
  });

  it('should use the last provider when there are multiple providers for same token', () => {
    const injector = createInjector([
      { provide: Engine, useClass: Engine },
      { provide: Engine, useClass: TurboEngine },
    ]);

    expect(injector.get(Engine)).toBeAnInstanceOf(TurboEngine);
  });

  it('should use non-type tokens', () => {
    const injector = createInjector([{ provide: 'token', useValue: 'value' }]);

    expect(injector.get('token')).toEqual('value');
  });

  it('should throw when given invalid providers', () => {
    expect(() => createInjector(['blah'] as any)).toThrowError(
      'Invalid provider - only instances of Provider and Type are allowed, got: blah'
    );
  });

  it('should provide itself', () => {
    const parent = createInjector([]);
    const child = parent.resolveAndCreateChild([]);

    expect(child.get(Injector)).toBe(child);
  });

  it('should throw when no provider defined', () => {
    const injector = createInjector([]);
    expect(() => injector.get('NonExisting')).toThrowError('No provider for NonExisting!');
  });

  it('should show the full path when no provider', () => {
    const injector = createInjector([CarWithDashboard, Engine, Dashboard]);
    expect(() => injector.get(CarWithDashboard)).toThrowError(
      `No provider for DashboardSoftware! (${stringify(CarWithDashboard)} -> ${stringify(
        Dashboard
      )} -> DashboardSoftware)`
    );
  });

  it('should throw when trying to instantiate a cyclic dependency', () => {
    const injector = createInjector([Car, { provide: Engine, useClass: CyclicEngine }]);

    expect(() => injector.get(Car)).toThrowError(
      `Cannot instantiate cyclic dependency! (${stringify(Car)} -> ${stringify(Engine)} -> ${stringify(Car)})`
    );
  });

  it('should show the full path when error happens in a constructor', () => {
    const providers = ReflectiveInjector.resolve([Car, { provide: Engine, useClass: BrokenEngine }]);

    const injector = new ReflectiveInjector_(providers);

    try {
      injector.get(Car);
      throw new Error('Must throw');
    } catch (e) {
      expect(e.message).toContain(`Error during instantiation of Engine! (${stringify(Car)} -> Engine)`);
      expect(getOriginalError(e) instanceof Error).toBeTruthy();
      expect(e.keys[0].token).toEqual(Engine);
    }
  });

  it('should instantiate an object after a failed attempt', () => {
    let isBroken = true;
    const callback = () => (isBroken ? new BrokenEngine() : new Engine());
    const injector = createInjector([Car, { provide: Engine, useFactory: callback }]);

    expect(() => injector.get(Car)).toThrowError(
      'Broken Engine: Error during instantiation of Engine! (Car -> Engine).'
    );

    isBroken = false;

    expect(injector.get(Car)).toBeAnInstanceOf(Car);
  });

  it('should support null values', () => {
    const injector = createInjector([{ provide: 'null', useValue: null }]);
    expect(injector.get('null')).toBe(null);
  });
});

describe('child', () => {
  it('should load instances from parent injector', () => {
    const parent = ReflectiveInjector.resolveAndCreate([Engine]);
    const child = parent.resolveAndCreateChild([]);

    const engineFromParent: Engine = parent.get(Engine);
    const engineFromChild: Engine = child.get(Engine);

    expect(engineFromChild).toBe(engineFromParent);
  });

  it('should not use the child providers when resolving the dependencies of a parent provider', () => {
    const parent = ReflectiveInjector.resolveAndCreate([Car, Engine]);
    const child = parent.resolveAndCreateChild([{ provide: Engine, useClass: TurboEngine }]);

    const carFromChild: Car = child.get(Car);
    expect(carFromChild.engine).toBeAnInstanceOf(Engine);
  });

  it('should create new instance in a child injector', () => {
    const parent = ReflectiveInjector.resolveAndCreate([Engine]);
    const child = parent.resolveAndCreateChild([{ provide: Engine, useClass: TurboEngine }]);

    const engineFromParent: TurboEngine = parent.get(Engine);
    const engineFromChild: TurboEngine = child.get(Engine);

    expect(engineFromParent).not.toBe(engineFromChild);
    expect(engineFromChild).toBeAnInstanceOf(TurboEngine);
  });

  it('should give access to parent', () => {
    const parent = ReflectiveInjector.resolveAndCreate([]);
    const child = parent.resolveAndCreateChild([]);
    expect(child.parent).toBe(parent);
  });
});

describe('resolveAndInstantiate', () => {
  it('should instantiate an object in the context of the injector', () => {
    const injector = ReflectiveInjector.resolveAndCreate([Engine]);
    const car: Car = injector.resolveAndInstantiate(Car);
    expect(car).toBeAnInstanceOf(Car);
    expect(car.engine).toBe(injector.get(Engine));
  });

  it('should not store the instantiated object in the injector', () => {
    const injector = ReflectiveInjector.resolveAndCreate([Engine]);
    injector.resolveAndInstantiate(Car);
    expect(() => injector.get(Car)).toThrowError();
  });
});

describe('instantiateResolved', () => {
  it('should instantiate an object in the context of the injector', () => {
    const injector = ReflectiveInjector.resolveAndCreate([Engine]);
    const car = injector.instantiateResolved(ReflectiveInjector.resolve([Car])[0]);
    expect(car).toBeAnInstanceOf(Car);
    expect(car.engine).toBe(injector.get(Engine));
  });
});

describe('depedency resolution', () => {
  describe('@Self()', () => {
    it('should return a dependency from self', () => {
      const injector = ReflectiveInjector.resolveAndCreate([
        Engine,
        { provide: Car, useFactory: (engine: Engine) => new Car(engine), deps: [[Engine, new Self()]] },
      ]);

      const car: Car = injector.get(Car);
      expect(car).toBeAnInstanceOf(Car);
      expect(car.engine).toBeAnInstanceOf(Engine);
    });

    it('should throw when not requested provider on self', () => {
      const parent = ReflectiveInjector.resolveAndCreate([Engine]);
      const child = parent.resolveAndCreateChild([
        { provide: Car, useFactory: (engine: Engine) => new Car(engine), deps: [[Engine, new Self()]] },
      ]);

      expect(() => child.get(Car)).toThrowError(`No provider for Engine! (${stringify(Car)} -> ${stringify(Engine)})`);
    });
  });

  describe('default', () => {
    it('should not skip self', () => {
      const parent = ReflectiveInjector.resolveAndCreate([Engine]);
      const child = parent.resolveAndCreateChild([
        { provide: Engine, useClass: TurboEngine },
        { provide: Car, useFactory: (engine: Engine) => new Car(engine), deps: [Engine] },
      ]);

      expect(child.get(Car).engine).toBeAnInstanceOf(TurboEngine);
    });
  });
});

describe('resolve', () => {
  it('should resolve and flatten', () => {
    const resolvedProviders = ReflectiveInjector.resolve([Engine, [BrokenEngine]]);
    resolvedProviders.forEach((provider) => {
      if (!provider) {
        return;
      } // the result is a sparse array
      expect(provider instanceof ResolvedReflectiveProvider_).toBe(true);
    });
  });

  it('should support multi providers', () => {
    const resolvedProvider = ReflectiveInjector.resolve([
      { provide: Engine, useClass: BrokenEngine, multi: true },
      { provide: Engine, useClass: TurboEngine, multi: true },
    ])[0];

    expect(resolvedProvider.key.token).toBe(Engine);
    expect(resolvedProvider.multiProvider).toEqual(true);
    expect(resolvedProvider.resolvedFactories.length).toEqual(2);
  });

  it('should support providers as hash', () => {
    const resolvedProvider = ReflectiveInjector.resolve([
      { provide: Engine, useClass: BrokenEngine, multi: true },
      { provide: Engine, useClass: TurboEngine, multi: true },
    ])[0];

    expect(resolvedProvider.key.token).toBe(Engine);
    expect(resolvedProvider.multiProvider).toEqual(true);
    expect(resolvedProvider.resolvedFactories.length).toEqual(2);
  });

  it('should support multi providers with only one provider', () => {
    const resolvedProvider = ReflectiveInjector.resolve([{ provide: Engine, useClass: BrokenEngine, multi: true }])[0];

    expect(resolvedProvider.key.token).toBe(Engine);
    expect(resolvedProvider.multiProvider).toEqual(true);
    expect(resolvedProvider.resolvedFactories.length).toEqual(1);
  });

  it('should throw when mixing multi providers with regular providers', () => {
    expect(() => {
      ReflectiveInjector.resolve([{ provide: Engine, useClass: BrokenEngine, multi: true }, Engine]);
    }).toThrowError(/Cannot mix multi providers and regular providers/);

    expect(() => {
      ReflectiveInjector.resolve([Engine, { provide: Engine, useClass: BrokenEngine, multi: true }]);
    }).toThrowError(/Cannot mix multi providers and regular providers/);
  });

  it('should resolve forward references', () => {
    const resolvedProviders = ReflectiveInjector.resolve([
      forwardRef(() => Engine),
      [{ provide: forwardRef(() => BrokenEngine), useClass: forwardRef(() => Engine) }],
      { provide: forwardRef(() => String), useFactory: () => 'OK', deps: [forwardRef(() => Engine)] },
    ]);

    const engineProvider = resolvedProviders[0];
    const brokenEngineProvider = resolvedProviders[1];
    const stringProvider = resolvedProviders[2];

    expect(engineProvider.resolvedFactories[0].factory() instanceof Engine).toBe(true);
    expect(brokenEngineProvider.resolvedFactories[0].factory() instanceof Engine).toBe(true);
    expect(stringProvider.resolvedFactories[0].dependencies[0].key).toEqual(ReflectiveKey.get(Engine));
  });

  it('should support overriding factory dependencies with dependency annotations', () => {
    const resolvedProviders = ReflectiveInjector.resolve([
      { provide: 'token', useFactory: (param: any) => 'result', deps: [[new Inject('dep')]] },
    ]);

    const resolvedProvider = resolvedProviders[0];

    expect(resolvedProvider.resolvedFactories[0].dependencies[0].key.token).toEqual('dep');
  });

  it('should allow declaring dependencies with flat arrays', () => {
    const resolvedProviders = ReflectiveInjector.resolve([
      { provide: 'token', useFactory: (param: any) => param, deps: [new Inject('dep')] },
    ]);

    const nestedResolved = ReflectiveInjector.resolve([
      { provide: 'token', useFactory: (param: any) => param, deps: [[new Inject('dep')]] },
    ]);

    expect(resolvedProviders[0].resolvedFactories[0].dependencies[0].key.token).toEqual(
      nestedResolved[0].resolvedFactories[0].dependencies[0].key.token
    );
  });
});

describe('displayName', () => {
  it('should work', () => {
    const injector = ReflectiveInjector.resolveAndCreate([Engine, BrokenEngine]) as ReflectiveInjector_;
    expect(injector.displayName).toEqual('ReflectiveInjector(providers: [ "Engine" ,  "BrokenEngine" ])');
  });
});

describe(`null as provider's value`, () => {
  it(`should works with "undefined"`, () => {
    const injector = ReflectiveInjector.resolveAndCreate([{ provide: Engine, useValue: undefined }]);

    expect(() => {
      injector.get(Engine); // Create cache
      injector.get(Engine); // Get from cache
    }).not.toThrow();
    expect(injector.get(Engine)).toBe(undefined);
  });

  it(`should works with "null"`, () => {
    const injector = ReflectiveInjector.resolveAndCreate([{ provide: Engine, useValue: null }]);

    expect(() => {
      injector.get(Engine); // Create cache
      injector.get(Engine); // Get from cache
    }).not.toThrow();
    expect(injector.get(Engine)).toBe(null);
  });

  it(`should works with "0"`, () => {
    const injector = ReflectiveInjector.resolveAndCreate([{ provide: Engine, useValue: 0 }]);

    expect(() => {
      injector.get(Engine); // Create cache
      injector.get(Engine); // Get from cache
    }).not.toThrow();
    expect(injector.get(Engine)).toBe(0);
  });

  it(`should works with ""`, () => {
    const injector = ReflectiveInjector.resolveAndCreate([{ provide: Engine, useValue: '' }]);

    expect(() => {
      injector.get(Engine); // Create cache
      injector.get(Engine); // Get from cache
    }).not.toThrow();
    expect(injector.get(Engine)).toBe('');
  });
});