升级到 Angular 10 后 rxjs 和 loadash CommonJS 或 AMD 依赖项优化警告

Question

我已将我的应用程序从 Angular 9 升级到 Angular 10。升级过程已成功，我能够运行该应用程序。但是当我发出ng serve 命令时，它会显示以下警告。

WARNING in src\app\auth\guard\auth.guard.ts depends on 'lodash'. CommonJS or AMD dependencies can cause optimization bailouts.
For more info see: https://angular.io/guide/build#configuring-commonjs-dependencies

WARNING in src\app\shared\services\api.service.ts depends on 'rxjs/Observable'. CommonJS or AMD dependencies can cause optimization bailouts.
For more info see: https://angular.io/guide/build#configuring-commonjs-dependencies

WARNING in src\app\auth\guard\auth.guard.ts depends on 'rxjs/observable/fromPromise'. CommonJS or AMD dependencies can cause optimization bailouts.
For more info see: https://angular.io/guide/build#configuring-commonjs-dependencies

WARNING in src\app\shared\services\localforage.service.ts depends on 'rxjs/observable/forkJoin'. CommonJS or AMD dependencies can cause optimization bailouts.
For more info see: https://angular.io/guide/build#configuring-commonjs-dependencies

WARNING in src\app\auth\guard\auth.guard.ts depends on 'rxjs/add/operator/map'. CommonJS or AMD dependencies can cause optimization bailouts.
For more info see: https://angular.io/guide/build#configuring-commonjs-dependencies

有一种解决方法是建议一些人将 commonJS 列入白名单，但它仍然会导致包大小的增加。我怎样才能摆脱这个常见的 JS 问题并仍然获得优化的包大小？

PS：最后的代码用map操作符

import { Router, CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';
import { switchMap, tap, map } from 'rxjs/operators';
import { Observable, from} from 'rxjs';

canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<boolean> {

        return this.getToken().map((token: any) => {
            if ((token !==null) && !this.jwtHelper.isTokenExpired(token.data)) {
               // this.proactiveTokenRefresh(token);
                return true;
            } 
            
            // Store the attempted URL for redirecting
            this.localForage.setItem('redirectUrl', state.url).then(() => {
                // Navigate to the login page
                this.router.navigate(['/login']);
                return false;
            });
        });
}
    
private getToken(): Observable<{}> {
    const token = this.localForage.getItem('id_token');
    
    return from(token);
}`

Answer 1

从警告中，下面会有所帮助

• 请检查您从rxjs 导入的所有内容

import {Observable, fromPromise} from 'rxjs' 
import {map, forkJoin} from 'rxjs/operators'

还要注意像下面这样管道你的操作符

import { Router, CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';

    import { switchMap, tap, map } from 'rxjs/operators';
    import { Observable, from} from 'rxjs';
    
    canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<boolean> {
    
      return this.getToken().pipe(
        map((token: any) => {
          if ((token !==null) && !this.jwtHelper.isTokenExpired(token.data)) {
            // this.proactiveTokenRefresh(token);
            return true;
          } 
          // Store the attempted URL for redirecting
          this.localForage.setItem('redirectUrl', state.url).then(() => {
            // Navigate to the login page
            this.router.navigate(['/login']);
            return false;
          });
        });
      )
    }
        
    private getToken(): Observable<{}> {
        const token = this.localForage.getItem('id_token');
        
        return from(token);
    }

• 对于lodash，尝试用各种ES2015可用函数替换lodash函数