Angular: Prevent route change if any changes made in the view
If your site needs prevent route change for multiple pages, i suppose it might be convenient to use this service:
import { Injectable } from '@angular/core';
import { CanActivateChild } from '@angular/router';
@Injectable()
export class NavPreventerService implements CanActivateChild {
locks: any = {};
constructor() {
// Bonus: If necessary also prevent closing the window:
window.addEventListener('beforeunload', (event) => {
if (this.hasRoutingLocks()) {
event.preventDefault();
event.returnValue = '';
}
});
}
canActivateChild() {
if (this.hasRoutingLocks()) {
if (confirm('Leave site?')) {
this.removeAllRoutingLocks();
return true;
}
return false;
}
return true;
}
setRoutingLock(key: string) {
this.locks[key] = true;
}
removeRoutingLock(key: string) {
delete this.locks[key];
}
removeAllRoutingLocks() {
this.locks = {};
}
hasRoutingLocks(): boolean {
return !!Object.keys(this.locks).length;
}
}
When it is necessary to prevent navigation, then in your component call
this.navPreventer.setRoutingLock('quiz-form');
Your application routing file should be like this:
export const appRoutesLocal: Routes = [
{path: '', canActivateChild: [NavPreventerService], children: [
{path: '', component: HomePageComponent},
]}
];
You can implement canDeactivate using typescript like
import { Injectable } from '@angular/core';
import { CanDeactivate } from '@angular/router';
import { ViewthatyouwantGuard } from './path to your view';
@Injectable()
export class ConfirmDeactivateGuard implements CanDeactivate<ViewthatyouwantGuard> {
canDeactivate(target: ViewthatyouwantGuard) {
if (target.hasChanges) {
return window.confirm('Do you really want to cancel?');
}
return true;
}
}
// hasChanges - function in 'ViewthatyouwantGuard' which will return true or false based on unsaved changes
// And in your routing file provide root like
{path:'rootPath/', component: ViewthatyouwantGuard, canDeactivate:[ConfirmDeactivateGuard]},
// Last but not least, also this guard needs to be registered accordingly:
@NgModule({
...
providers: [
...
ConfirmDeactivateGuard
]
})
export class AppModule {}
Source: https://blog.thoughtram.io/angular/2016/07/18/guards-in-angular-2.html
CanDeactivate
can be used for that. You need to pass the status to a service that is accessible to canDeactivate
.