In Angular 6 how make case insensitive url pattern?

You need a UrlSerializer as follow:

import { DefaultUrlSerializer, UrlTree } from '@angular/router';


 export class LowerCaseUrlSerializer extends DefaultUrlSerializer {
   parse(url: string): UrlTree {
      return super.parse(url.toLowerCase());
  }
}

And then added it as a provider in the app.module.ts

providers: [
 {
   provide: UrlSerializer,
   useClass: LowerCaseUrlSerializer
}
]

You should add this provide statement to the app.module.ts

    import { DefaultUrlSerializer, UrlTree } from '@angular/router';
    
    export class LowerCaseUrlSerializer extends DefaultUrlSerializer {
        parse(url: string): UrlTree {
            // Optional Step: Do some stuff with the url if needed.
    
            // If you lower it in the optional step 
            // you don't need to use "toLowerCase" 
            // when you pass it down to the next function
            return super.parse(url.toLowerCase()); 
        }
    }

And

    @NgModule({
        imports: [
          ...
        ],
        declarations: [AppComponent],
        providers: [
            {
                provide: UrlSerializer,
                useClass: LowerCaseUrlSerializer
            }
        ],
        bootstrap: [AppComponent]
    })

This will work, configure the route to NotFoundComponent with wild character like below

{path:'**',component:NotFoundComponent}

then, in the NotFoundComponent.ts file, add the below lines inside ngOnInit()

if(this.route.snapshot.url[0].path.toLowerCase()!==this.route.snapshot.url[0].path)
      this.router.navigate([this.route.snapshot.url[0].path.toLowerCase()]);

You have to import ActivatedRoute,Router from '@angular/router' and inject in constructor like below

constructor(private route:ActivatedRoute,
    private router:Router) { }

Here if condition in ngOnInit() makes sure that it won't route or navigate infinitely

Inspired by this thread, the following variant is supposed to lower-case only the UrlSegments in the URL part - and leave the query params alone.

The idea is to let DefaultUrlSerializer parse the URL to an UrlTree - and then go through the UrlTree and lowercase segments.

export class LowerCaseUrlSerializer extends DefaultUrlSerializer {
    parse(url: string): UrlTree {
        const urlTree = super.parse(url);

        this.lowerCaseSegments(urlTree.root);

        return urlTree;
    }
    private lowerCaseSegments(urlSegmentGroup: UrlSegmentGroup) {
        if (urlSegmentGroup.hasChildren()) {
            Object.entries(urlSegmentGroup.children).forEach(
                ([key, value]) => this.lowerCaseSegments(value)
            );
        }

        urlSegmentGroup.segments.forEach((segment) => segment.path = segment.path.toLowerCase());
    }
}