angularのroutingに挟むguard

> ng generate guard guard-name

が使える

生成された後はこんな感じで書いて

import { Injectable } from '@angular/core';
import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot, UrlTree,  Router } from '@angular/router';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class MyAuthGuard implements CanActivate {
  constructor(private router: Router) {}

  canActivate(
    next: ActivatedRouteSnapshot,
    state: RouterStateSnapshot): Observable<boolean | UrlTree> | Promise<boolean | UrlTree> | boolean | UrlTree {
    // return false;
    return this.router.parseUrl('/auth?url='+state.url);
  }
  
}

こんな感じで書けばOK
app.routing.ts

export const routes: Routes = [
  {
    path: 'pages',
    component: Pages,
    canActivate: [MyAuthGuard],