Q:

Angular 5: fade animation during routing (CSS)

I have 2 routes :
export const appRoutes: Route[] = [
{
                path: 'page1',
                component: Page1Component,
                data: {
                    animation: 'page1'
                }
            },
{
                path: 'page2',
                component: Page2Component,
                data: {
                    animation: 'page2'
                }
            },
];

My Route animation :
export const routeStateTrigger = trigger('routeState', [
    transition('* => *', [
        query(':enter', [
            style({ position: 'absolute', opacity: 0 })
        ], { optional: true }),
        query(':leave', [
            animate(300, style({ opacity: 0 }))
        ], { optional: true }),
        query(':enter', [
            style({ position: 'relative', opacity: 0 }),
            animate(300, style({ display: 'visible', opacity: 1 }))
        ], { optional: true })
    ])
]);

My router-outlet :
<div [@routeState]="getAnimationData(routerOutlet)">
    <router-outlet #routerOutlet="outlet"></router-outlet>
</div>

and getAnimationData method :
getAnimationData(routerOutlet: RouterOutlet) {
    const routeData = routerOutlet.activatedRouteData['animation'];
    return routeData ? routeData : 'rootPage';
}

This works well, except page transition occurs in two steps (sequential) :

page1 disappears (300 ms)
AND THEN page2 appears (300 ms)

What I want is the disappearing of page1 should happen the same time page2 appears, the transitions should occur simultaneously.
Problem :
I want to prevent the TEMPORARY RESIZING of the content of page1 or page2.
Explanation :
When animating with group() to make them appear-disappear simultaneously AND setting the position temporarily to 'absolute' then the content resizes (because the content is width 100%, and when the container size changes the content changes as well).
I've tried playing with z-index :
position: 'relative', 'z-index': 1

but that didn't work, it's still stacking entering page below leaving page.
Is there a good solution to this ?

A:

Try this simple transition. 
export const routeStateTrigger =
  // trigger name for attaching this animation to an element using the [@triggerName] syntax
  trigger('routeState', [

    // route 'enter and leave (<=>)' transition
    transition('*<=>*', [

      // css styles at start of transition
      style({ opacity: 0 }),

      // animation and styles at end of transition
      animate('0.4s', style({ opacity: 1 }))
    ]),
  ]);

A:

I finally made it work :
export const routeStateTrigger = trigger('routeState', [
    transition('* => *', [
        query(':enter', [
                style({ opacity: 0 })
            ], { optional: true }
        ),
        group([
            query(':leave', [
                    animate(300, style({ opacity: 0 }))
                ],
                { optional: true }
            ),
            query(':enter', [
                    style({ opacity: 0 }),
                    animate(300, style({ opacity: 1 }))
                ],
                { optional: true }
            )
        ])
    ])
]);

This CSS selector did the trick :
/deep/ router-outlet~* {
    position: absolute;
    width: 100%;
    height: 100%;
}

