# All files / core/injector injector.ts

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82.72% Branches 67/81
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     import {
      OPTIONAL_DEPS_METADATA,
      OPTIONAL_PROPERTY_DEPS_METADATA,
      PARAMTYPES_METADATA,
      PROPERTY_DEPS_METADATA,
      SELF_DECLARED_DEPS_METADATA,
    } from '@nestjs/common/constants';
    import { Controller } from '@nestjs/common/interfaces/controllers/controller.interface';
    import { Injectable } from '@nestjs/common/interfaces/injectable.interface';
    import { Type } from '@nestjs/common/interfaces/type.interface';
    import {
      isFunction,
      isNil,
      isObject,
      isUndefined,
    } from '@nestjs/common/utils/shared.utils';
    import { RuntimeException } from '../errors/exceptions/runtime.exception';
    import { UndefinedDependencyException } from '../errors/exceptions/undefined-dependency.exception';
    import { UnknownDependenciesException } from '../errors/exceptions/unknown-dependencies.exception';
    import { MiddlewareWrapper } from '../middleware/container';
    import { InstanceWrapper } from './container';
    import { Module } from './module';

    /**
     * The type of an injectable dependency
     */
    export type InjectorDependency = Type<any> | Function | string;

    /**
     * The property-based dependency
     */
    export interface PropertyDependency {
      key: string;
      name: InjectorDependency;
      isOptional?: boolean;
      instance?: any;
    }

    /**
     * Context of a dependency which gets injected by
     * the injector
     */
    export interface InjectorDependencyContext {
      /**
       * The name of the property key (property-based injection)
       */
      key?: string;
      /**
       * The name of the function or injection token
       */
      name?: string;
      /**
       * The index of the dependency which gets injected
       * from the dependencies array
       */
      index?: number;
      /**
       * The dependency array which gets injected
       */
      dependencies?: InjectorDependency[];
    }

    export class Injector {
      public async loadInstanceOfMiddleware(
        wrapper: MiddlewareWrapper,
        collection: Map<string, MiddlewareWrapper>,
        module: Module,
      ) {
        const { metatype } = wrapper;
        const currentMetatype = collection.get(metatype.name);
        if (currentMetatype.instance !== null) {
          return;
        }
        await this.resolveConstructorParams(
          wrapper as any,
          module,
          null,
          instances => {
            collection.set(metatype.name, {
              instance: new metatype(...instances),
              metatype,
            });
          },
        );
      }

      public async loadInstanceOfRoute(
        wrapper: InstanceWrapper<Controller>,
        module: Module,
      ) {
        const routes = module.routes;
        await this.loadInstance<Controller>(wrapper, routes, module);
      }

      public async loadInstanceOfInjectable(
        wrapper: InstanceWrapper<Controller>,
        module: Module,
      ) {
        const injectables = module.injectables;
        await this.loadInstance<Controller>(wrapper, injectables, module);
      }

      public loadPrototypeOfInstance<T>(
        { metatype, name }: InstanceWrapper<T>,
        collection: Map<string, InstanceWrapper<T>>,
      ) {
        if (!collection) {
          return null;
        }
        const target = collection.get(name);
        if (target.isResolved || !isNil(target.inject) || !metatype.prototype) {
          return null;
        }
        collection.set(name, {
          ...collection.get(name),
          instance: Object.create(metatype.prototype),
        });
      }

      public async loadInstanceOfComponent(
        wrapper: InstanceWrapper<Injectable>,
        module: Module,
      ) {
        const components = module.components;
        await this.loadInstance<Injectable>(wrapper, components, module);
      }

      public applyDoneHook<T>(wrapper: InstanceWrapper<T>): () => void {
        let done: () => void;
        wrapper.done$ = new Promise<void>((resolve, reject) => {
          done = resolve;
        });
        wrapper.isPending = true;
        return done;
      }

      public async loadInstance<T>(
        wrapper: InstanceWrapper<T>,
        collection: Map<string, InstanceWrapper<any>>,
        module: Module,
      ) {
        if (wrapper.isPending) {
          return wrapper.done$;
        }
        const done = this.applyDoneHook(wrapper);
        const { name, inject } = wrapper;

        const targetWrapper = collection.get(name);
        if (isUndefined(targetWrapper)) {
          throw new RuntimeException();
        }
        if (targetWrapper.isResolved) {
          return;
        }
        const callback = async instances => {
          const properties = await this.resolveProperties(wrapper, module, inject);
          const instance = await this.instantiateClass(
            instances,
            wrapper,
            targetWrapper,
          );
          this.applyProperties(instance, properties);
          done();
        };
        await this.resolveConstructorParams<T>(wrapper, module, inject, callback);
      }

      public async resolveConstructorParams<T>(
        wrapper: InstanceWrapper<T>,
        module: Module,
        inject: InjectorDependency[],
        callback: (args) => void,
      ) {
        const dependencies = isNil(inject)
          ? this.reflectConstructorParams(wrapper.metatype)
          : inject;
        const optionalDependenciesIds = isNil(inject)
          ? this.reflectOptionalParams(wrapper.metatype)
          : [];

        let isResolved = true;
        const instances = await Promise.all(
          dependencies.map(async (param, index) => {
            try {
              const paramWrapper = await this.resolveSingleParam<T>(
                wrapper,
                param,
                { index, dependencies },
                module,
              );
              Iif (!paramWrapper.isResolved && !paramWrapper.forwardRef) {
                isResolved = false;
              }
              return paramWrapper.instance;
            } catch (err) {
              const isOptional = optionalDependenciesIds.includes(index);
              if (!isOptional) {
                throw err;
              }
              return undefined;
            }
          }),
        );
        isResolved && (await callback(instances));
      }

      public reflectConstructorParams<T>(type: Type<T>): any[] {
        const paramtypes = Reflect.getMetadata(PARAMTYPES_METADATA, type) || [];
        const selfParams = this.reflectSelfParams<T>(type);

        selfParams.forEach(({ index, param }) => (paramtypes[index] = param));
        return paramtypes;
      }

      public reflectOptionalParams<T>(type: Type<T>): any[] {
        return Reflect.getMetadata(OPTIONAL_DEPS_METADATA, type) || [];
      }

      public reflectSelfParams<T>(type: Type<T>): any[] {
        return Reflect.getMetadata(SELF_DECLARED_DEPS_METADATA, type) || [];
      }

      public async resolveSingleParam<T>(
        wrapper: InstanceWrapper<T>,
        param: Type<any> | string | symbol | any,
        dependencyContext: InjectorDependencyContext,
        module: Module,
      ) {
        if (isUndefined(param)) {
          throw new UndefinedDependencyException(
            wrapper.name,
            dependencyContext,
            module,
          );
        }
        const token = this.resolveParamToken(wrapper, param);
        return this.resolveComponentInstance<T>(
          module,
          isFunction(token) ? (token as Type<any>).name : token,
          dependencyContext,
          wrapper,
        );
      }

      public resolveParamToken<T>(
        wrapper: InstanceWrapper<T>,
        param: Type<any> | string | symbol | any,
      ) {
        if (!param.forwardRef) {
          return param;
        }
        wrapper.forwardRef = true;
        return param.forwardRef();
      }

      public async resolveComponentInstance<T>(
        module: Module,
        name: any,
        dependencyContext: InjectorDependencyContext,
        wrapper: InstanceWrapper<T>,
      ) {
        const components = module.components;
        const instanceWrapper = await this.lookupComponent(
          components,
          module,
          { ...dependencyContext, name },
          wrapper,
        );
        if (!instanceWrapper.isResolved && !instanceWrapper.forwardRef) {
          await this.loadInstanceOfComponent(instanceWrapper, module);
        }
        if (instanceWrapper.async) {
          instanceWrapper.instance = await instanceWrapper.instance;
        }
        return instanceWrapper;
      }

      public async lookupComponent<T = any>(
        components: Map<string, any>,
        module: Module,
        dependencyContext: InjectorDependencyContext,
        wrapper: InstanceWrapper<T>,
      ) {
        const { name } = dependencyContext;
        const scanInExports = () =>
          this.lookupComponentInExports(dependencyContext, module, wrapper);
        return components.has(name) ? components.get(name) : scanInExports();
      }

      public async lookupComponentInExports<T = any>(
        dependencyContext: InjectorDependencyContext,
        module: Module,
        wrapper: InstanceWrapper<T>,
      ) {
        const instanceWrapper = await this.lookupComponentInRelatedModules(
          module,
          dependencyContext.name,
        );
        if (isNil(instanceWrapper)) {
          throw new UnknownDependenciesException(
            wrapper.name,
            dependencyContext,
            module,
          );
        }
        return instanceWrapper;
      }

      public async lookupComponentInRelatedModules(
        module: Module,
        name: any,
        moduleRegistry = [],
      ) {
        let componentRef = null;

        const relatedModules: Set<Module> = module.relatedModules || new Set();
        const children = [...relatedModules.values()].filter(item => item);
        for (const relatedModule of children) {
          Iif (moduleRegistry.includes(relatedModule.id)) {
            continue;
          }
          moduleRegistry.push(relatedModule.id);
          const { components, exports } = relatedModule;
          if (!exports.has(name) || !components.has(name)) {
            const instanceRef = await this.lookupComponentInRelatedModules(
              relatedModule,
              name,
              moduleRegistry,
            );
            Iif (instanceRef) {
              return instanceRef;
            }
            continue;
          }
          componentRef = components.get(name);
          if (!componentRef.isResolved && !componentRef.forwardRef) {
            await this.loadInstanceOfComponent(componentRef, relatedModule);
            break;
          }
        }
        return componentRef;
      }

      public async resolveProperties<T>(
        wrapper: InstanceWrapper<T>,
        module: Module,
        inject?: InjectorDependency[],
      ): Promise<PropertyDependency[]> {
        Iif (!isNil(inject)) {
          return [];
        }
        const properties = this.reflectProperties(wrapper.metatype);
        const instances = await Promise.all(
          properties.map(async (item: PropertyDependency) => {
            try {
              const dependencyContext = {
                key: item.key,
                name: item.name as string,
              };
              const paramWrapper = await this.resolveSingleParam<T>(
                wrapper,
                item.name,
                dependencyContext,
                module,
              );
              return (paramWrapper && paramWrapper.instance) || undefined;
            } catch (err) {
              if (!item.isOptional) {
                throw err;
              }
              return undefined;
            }
          }),
        );
        return properties.map((item: PropertyDependency, index: number) => ({
          ...item,
          instance: instances[index],
        }));
      }

      public reflectProperties<T>(type: Type<T>): PropertyDependency[] {
        const properties = Reflect.getMetadata(PROPERTY_DEPS_METADATA, type) || [];
        const optionalKeys: string[] =
          Reflect.getMetadata(OPTIONAL_PROPERTY_DEPS_METADATA, type) || [];

        return properties.map(item => ({
          ...item,
          name: item.type,
          isOptional: optionalKeys.includes(item.key),
        }));
      }

      public applyProperties<T = any>(
        instance: T,
        properties: PropertyDependency[],
      ) {
        if (!isObject(instance)) {
          return undefined;
        }
        properties
          .filter(item => !isNil(item.instance))
          .forEach(item => (instance[item.key] = item.instance));
      }

      public async instantiateClass<T = any>(
        instances: any[],
        wrapper: InstanceWrapper<any>,
        targetMetatype: InstanceWrapper<any>,
      ): Promise<T> {
        const { metatype, inject } = wrapper;
        Eif (isNil(inject)) {
          targetMetatype.instance = wrapper.forwardRef
            ? Object.assign(targetMetatype.instance, new metatype(...instances))
            : new metatype(...instances);
        } else {
          const factoryResult = ((targetMetatype.metatype as any) as Function)(
            ...instances,
          );
          targetMetatype.instance = await factoryResult;
        }
        targetMetatype.isResolved = true;
        return targetMetatype.instance;
      }
    }