javascript - Angular 5 Scroll to top on every Route click

Question

I am using angular 5. I have a dashboard where I have few sections with small content and few sections with so large content that I am facing a problem when changing router while going to top. Every time I need to scroll to go to top. Can anyone help me to solve this issue so that when I change the router my view always stay at the top.

Thanks in advance.

Answer 1

There are some solutions, make sure to check them all :)

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The router outlet will emit the activate event any time a new component is being instantiated, so we could use (activate) to scroll (for example) to the top:

app.component.html

<router-outlet (activate)="onActivate($event)" ></router-outlet>

app.component.ts

onActivate(event) {
    window.scroll(0,0);
    //or document.body.scrollTop = 0;
    //or document.querySelector('body').scrollTo(0,0)
    ...
}

Use, for exemple, this solution for a smooth scroll:

    onActivate(event) {
        let scrollToTop = window.setInterval(() => {
            let pos = window.pageYOffset;
            if (pos > 0) {
                window.scrollTo(0, pos - 20); // how far to scroll on each step
            } else {
                window.clearInterval(scrollToTop);
            }
        }, 16);
    }

---

If you wish to be selective, say not every component should trigger the scrolling, you can check it in an if statement like this:

onActivate(e) {
    if (e.constructor.name)==="login"{ // for example
            window.scroll(0,0);
    }
}

---

Since Angular6.1, we can also use { scrollPositionRestoration: 'enabled' } on eagerly loaded modules and it will be applied to all routes:

RouterModule.forRoot(appRoutes, { scrollPositionRestoration: 'enabled' })

It will also do the smooth scrolling, already. However this has the inconvenient for doing it on every routing.

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An other solution is to do the top scrolling on router animation. Add this in every transition where you want to scroll to the top:

query(':enter, :leave', style({ position: 'fixed' }), { optional: true })