chore: use conditional nullish operators

examples/access-control-migration/src/components/casbin-authorization/services/casbin.authorizer.ts

@@ -44,7 +44,7 @@ export class CasbinAuthorizationProvider implements Provider<Authorizer> {
     const request: AuthorizationRequest = {
       subject,
       object,
-      action: (metadata.scopes && metadata.scopes[0]) || DEFAULT_SCOPE,
+      action: metadata.scopes?.[0] ?? DEFAULT_SCOPE,
     };
 
     const allowedRoles = metadata.allowedRoles;

examples/greeter-extension/src/greeters/greeter-cn.ts

@@ -30,7 +30,7 @@ export class ChineseGreeter implements Greeter {
   ) {}
 
   greet(name: string) {
-    if (this.options && this.options.nameFirst === false) {
+    if (this.options?.nameFirst === false) {
       return `你好，${name}！`;
     }
     return `${name}，你好！`;

examples/greeter-extension/src/greeting-service.ts

@@ -3,7 +3,7 @@
 // This file is licensed under the MIT License.
 // License text available at https://opensource.org/licenses/MIT
 
-import {config, Getter, extensionPoint, extensions} from '@loopback/core';
+import {config, extensionPoint, extensions, Getter} from '@loopback/core';
 import chalk from 'chalk';
 import {Greeter, GREETER_EXTENSION_POINT_NAME} from './types';
 
@@ -60,7 +60,7 @@ export class GreetingService {
       // Fall back to English
       greeting = `Hello, ${name}!`;
     }
-    if (this.options && this.options.color) {
+    if (this.options?.color) {
       greeting = chalk.keyword(this.options.color)(greeting);
     }
     return greeting;

examples/hello-world/src/application.ts

@@ -23,7 +23,7 @@ export class HelloWorldApplication extends RestApplication {
   async start() {
     await super.start();
 
-    if (!(this.options && this.options.disableConsoleLog)) {
+    if (!this.options?.disableConsoleLog) {
       const rest = await this.getServer(RestServer);
       console.log(
         `REST server running on port: ${await rest.get('rest.port')}`,

examples/log-extension/src/mixins/log.mixin.ts

@@ -23,7 +23,7 @@ export function LogMixin<T extends MixinTarget<Application>>(superClass: T) {
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     constructor(...args: any[]) {
       super(...args);
-      if (this.options && this.options.logLevel) {
+      if (this.options?.logLevel) {
         this.logLevel(this.options.logLevel);
       }
       this.component(LogComponent);

examples/passport-login/src/sequence.ts

@@ -45,7 +45,7 @@ export class MySequence implements SequenceHandler {
       const args = await this.parseParams(request, route);
 
       // if provider name is available in the request path params, set it in the query
-      if (route.pathParams && route.pathParams.provider) {
+      if (route.pathParams?.provider) {
         request.query['oauth2-provider-name'] = route.pathParams.provider;
       }
 

examples/passport-login/src/services/user.service.ts

@@ -3,11 +3,11 @@
 // This file is licensed under the MIT License.
 // License text available at https://opensource.org/licenses/MIT
 
+import {UserIdentityService} from '@loopback/authentication';
 import {repository} from '@loopback/repository';
 import {Profile as PassportProfile} from 'passport';
-import {UserIdentityService} from '@loopback/authentication';
-import {UserRepository} from '../repositories';
 import {User} from '../models';
+import {UserRepository} from '../repositories';
 import {UserIdentityRepository} from '../repositories/user-identity.repository';
 
 /**
@@ -43,10 +43,9 @@ export class PassportUserIdentityService
     });
     let user: User;
     if (!users || !users.length) {
-      const name =
-        profile.name && profile.name.givenName
-          ? profile.name.givenName + ' ' + profile.name.familyName
-          : profile.displayName;
+      const name = profile.name?.givenName
+        ? profile.name.givenName + ' ' + profile.name.familyName
+        : profile.displayName;
       user = await this.userRepository.create({
         email: email,
         name: name || JSON.stringify(profile.name),

examples/rpc-server/src/rpc.server.ts

@@ -4,10 +4,10 @@
 // License text available at https://opensource.org/licenses/MIT
 
 import {
-  Context,
-  inject,
   Application,
+  Context,
   CoreBindings,
+  inject,
   Server,
 } from '@loopback/core';
 import {once} from 'events';
@@ -35,9 +35,7 @@ export class RPCServer extends Context implements Server {
   }
 
   async start(): Promise<void> {
-    this._server = this.expressServer.listen(
-      (this.config && this.config.port) || 3000,
-    );
+    this._server = this.expressServer.listen(this.config?.port ?? 3000);
     this._listening = true;
     await once(this._server, 'listening');
   }

extensions/authentication-passport/src/__tests__/unit/fixtures/mock-passport-strategy.ts

@@ -6,8 +6,8 @@
 // Should it be imported from 'express'?
 // The `Request` type from 'express' is not compatible
 // with the one from `@loopback/rest` now.
-import {UserProfile} from '@loopback/security';
 import {Request} from '@loopback/rest';
+import {UserProfile} from '@loopback/security';
 import {AuthenticateOptions, Strategy} from 'passport';
 
 /**
@@ -39,18 +39,10 @@ export class MockPassportStrategy extends Strategy {
    * pass req.query.testState = 'error' to mock unexpected error
    */
   async verify(request: Request) {
-    if (
-      request.headers &&
-      request.headers.testState &&
-      request.headers.testState === 'fail'
-    ) {
+    if (request.headers?.testState === 'fail') {
       this.returnUnauthorized('authorization failed');
       return;
-    } else if (
-      request.headers &&
-      request.headers.testState &&
-      request.headers.testState === 'error'
-    ) {
+    } else if (request.headers?.testState === 'error') {
       this.returnError('unexpected error');
       return;
     }

extensions/metrics/src/metrics.component.ts

@@ -31,22 +31,16 @@ export class MetricsComponent implements Component {
     @config()
     options: MetricsOptions = DEFAULT_METRICS_OPTIONS,
   ) {
-    if (
-      !options.defaultMetrics ||
-      (options.defaultMetrics && !options.defaultMetrics.disabled)
-    ) {
+    if (!options.defaultMetrics || !options.defaultMetrics?.disabled) {
       this.application.lifeCycleObserver(MetricsObserver);
     }
-    if (
-      !options.pushGateway ||
-      (options.pushGateway && !options.pushGateway.disabled)
-    ) {
+    if (!options.pushGateway || !options.pushGateway?.disabled) {
       this.application.lifeCycleObserver(MetricsPushObserver);
     }
     this.application.add(createBindingFromClass(MetricsInterceptor));
-    if (!options.endpoint || (options.endpoint && !options.endpoint.disabled)) {
+    if (!options.endpoint || !options.endpoint?.disabled) {
       this.application.controller(
-        metricsControllerFactory(options.endpoint && options.endpoint.basePath),
+        metricsControllerFactory(options.endpoint?.basePath),
       );
     }
   }

packages/authorization/src/__tests__/acceptance/authorization-casbin.acceptance.ts

@@ -4,11 +4,11 @@
 // License text available at https://opensource.org/licenses/MIT
 
 import {
+  Application,
   Context,
   inject,
   invokeMethod,
   Provider,
-  Application,
 } from '@loopback/core';
 import {SecurityBindings, securityId, UserProfile} from '@loopback/security';
 import {expect} from '@loopback/testlab';
@@ -151,7 +151,7 @@ describe('Authorization', () => {
       const request: AuthorizationRequest = {
         subject: authorizationCtx.principals[0].name,
         object: metadata.resource ?? authorizationCtx.resource,
-        action: (metadata.scopes && metadata.scopes[0]) || 'execute',
+        action: metadata.scopes?.[0] ?? 'execute',
       };
       const allow = await this.enforcer.enforce(
         request.subject,

packages/boot/src/bootstrapper.ts

@@ -4,11 +4,11 @@
 // License text available at https://opensource.org/licenses/MIT
 
 import {
+  Application,
   Context,
+  CoreBindings,
   inject,
   resolveList,
-  Application,
-  CoreBindings,
 } from '@loopback/core';
 import debugModule from 'debug';
 import {resolve} from 'path';
@@ -79,11 +79,7 @@ export class Bootstrapper {
 
     // Determine the phases to be run. If a user set a phases filter, those
     // are selected otherwise we run the default phases (BOOTER_PHASES).
-    const phases = execOptions
-      ? execOptions.filter && execOptions.filter.phases
-        ? execOptions.filter.phases
-        : BOOTER_PHASES
-      : BOOTER_PHASES;
+    const phases = execOptions?.filter?.phases ?? BOOTER_PHASES;
 
     // Find booters registered to the BOOTERS_TAG by getting the bindings
     const bindings = bootCtx.findByTag(BootTags.BOOTER);
@@ -100,7 +96,7 @@ export class Bootstrapper {
     // names of booters that should be run), that is the value, otherwise it
     // is all the registered booters by default.
     const names = execOptions
-      ? execOptions.filter && execOptions.filter.booters
+      ? execOptions.filter?.booters
         ? execOptions.filter.booters
         : defaultBooterNames
       : defaultBooterNames;

packages/context/src/binding-inspector.ts

@@ -178,7 +178,7 @@ export function bindingTemplateFor<T>(
     for (const t of templateFunctions) {
       binding.apply(t);
     }
-    if (spec && spec.target !== cls) {
+    if (spec?.target !== cls) {
       // Remove name/key tags inherited from base classes
       binding.apply(removeNameAndKeyTags);
     }

packages/context/src/context.ts

@@ -502,7 +502,7 @@ export class Context extends EventEmitter {
       if (filter(b)) bindings.push(b);
     }
 
-    const parentBindings = this._parent && this._parent.find(filter);
+    const parentBindings = this._parent?.find(filter);
     return this._mergeWithParent(bindings, parentBindings);
   }
 

packages/context/src/inject-config.ts

@@ -129,7 +129,7 @@ export namespace config {
  */
 function getCurrentBindingKey(session: ResolutionSession) {
   // The current binding is not set if `instantiateClass` is invoked directly
-  return session.currentBinding && session.currentBinding.key;
+  return session.currentBinding?.key;
 }
 
 /**

packages/express/src/express.server.ts

@@ -95,7 +95,7 @@ export class ExpressServer extends BaseMiddlewareRegistry implements Server {
    * will be 'http://localhost:3000' regardless of the `basePath`.
    */
   get rootUrl(): string | undefined {
-    return this.httpServer && this.httpServer.url;
+    return this.httpServer?.url;
   }
 
   async start() {

packages/http-server/src/http-server.ts

@@ -152,15 +152,15 @@ export class HttpServer {
    */
   public get port(): number {
     if (typeof this._address === 'string') return 0;
-    return (this._address && this._address.port) || this.serverOptions.port!;
+    return this._address?.port || this.serverOptions.port!;
   }
 
   /**
    * Host of the HTTP / HTTPS server
    */
   public get host(): string | undefined {
     if (typeof this._address === 'string') return undefined;
-    return (this._address && this._address.address) || this.serverOptions.host;
+    return this._address?.address || this.serverOptions.host;
   }
 
   /**

packages/metadata/src/decorator-factory.ts

@@ -98,7 +98,7 @@ export class DecoratorFactory<
   }
 
   protected allowInheritance(): boolean {
-    return !!(this.options && this.options.allowInheritance);
+    return !!this.options?.allowInheritance;
   }
 
   /**

packages/openapi-v3/src/build-responses-from-metadata.ts

@@ -21,7 +21,7 @@ declare type ResponseMap = Map<
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 function isModel<T extends Model>(c: any): c is T {
-  return c && c.prototype instanceof Model;
+  return c?.prototype instanceof Model;
 }
 
 /**

packages/openapi-v3/src/controller-spec.ts

@@ -194,7 +194,7 @@ function resolveControllerSpec(constructor: Function): ControllerSpec {
     }
 
     if (methodTags) {
-      if (operationSpec.tags && operationSpec.tags.length) {
+      if (operationSpec.tags?.length) {
         operationSpec.tags = operationSpec.tags.concat(methodTags.tags);
       } else {
         operationSpec.tags = methodTags.tags;

packages/openapi-v3/src/decorators/response.decorator.ts

@@ -20,8 +20,7 @@ interface ResponseWithContent extends ResponseObject {
 }
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 function isResponseObject(c: any): c is ResponseWithContent {
-  // eslint-disable-next-line no-prototype-builtins
-  return !!c && c.hasOwnProperty('content') && !!c.content;
+  return !!c?.hasOwnProperty('content') && !!c.content;
 }
 
 function buildDecoratorReducer(

packages/repository-json-schema/src/build-schema.ts

@@ -342,12 +342,12 @@ function buildSchemaTitle<T extends object>(
 function getTitleSuffix<T extends object>(options: JsonSchemaOptions<T> = {}) {
   let suffix = '';
 
-  if (options.optional && options.optional.length) {
+  if (options.optional?.length) {
     suffix += `Optional_${options.optional.join('-')}_`;
   } else if (options.partial) {
     suffix += 'Partial';
   }
-  if (options.exclude && options.exclude.length) {
+  if (options.exclude?.length) {
     suffix += `Excluding_${options.exclude.join('-')}_`;
   }
   if (options.includeRelations) {
@@ -463,7 +463,7 @@ export function modelToJsonSchema<T extends object>(
   }
 
   for (const p in meta.properties) {
-    if (options.exclude && options.exclude.includes(p as keyof T)) {
+    if (options.exclude?.includes(p as keyof T)) {
       debug('Property % is excluded by %s', p, options.exclude);
       continue;
     }
@@ -562,7 +562,7 @@ export function modelToJsonSchema<T extends object>(
     if (!schema || !Object.keys(schema).length) return;
 
     // promote nested definition to the top level
-    if (result !== schema && schema.definitions) {
+    if (result !== schema?.definitions) {
       for (const key in schema.definitions) {
         if (key === title) continue;
         result.definitions = result.definitions ?? {};

packages/repository-tests/src/crud/transactions.suite.ts

@@ -77,7 +77,7 @@ export function transactionSuite(
           // reference of a `tx`.
           // Detailed explanation see:
           // https://github.com/strongloop/loopback-next/pull/4474
-          if (ds.connector && ds.connector.name === 'postgresql') {
+          if (ds.connector?.name === 'postgresql') {
             tx = undefined;
           }
           if (tx?.isActive()) {

packages/repository/src/model.ts

@@ -216,7 +216,7 @@ function asObject(value: any, options?: Options): any {
  */
 export abstract class Model {
   static get modelName(): string {
-    return (this.definition && this.definition.name) || this.name;
+    return this.definition?.name || this.name;
   }
 
   static definition: ModelDefinition;
@@ -268,7 +268,7 @@ export abstract class Model {
     const def = (this.constructor as typeof Model).definition;
     const obj: AnyObject = {};
 
-    if (options && options.ignoreUnknownProperties === false) {
+    if (options?.ignoreUnknownProperties === false) {
       const hiddenProperties: string[] = def?.settings.hiddenProperties || [];
       for (const p in this) {
         if (!hiddenProperties.includes(p)) {

packages/repository/src/relations/has-many/has-many.helpers.ts

@@ -34,8 +34,7 @@ export function resolveHasManyMetadata(
   relationMeta = resolveHasManyMetaHelper(relationMeta);
 
   const targetModel = relationMeta.target();
-  const targetModelProperties =
-    targetModel.definition && targetModel.definition.properties;
+  const targetModelProperties = targetModel.definition?.properties;
 
   const sourceModel = relationMeta.source;