Here is a random animation I've made
    import { trigger, animate, transition, style, keyframes} from '@angular/animations';
    export const customAnimation=
        trigger('customAnimation', [
            transition(':leave', [
                style({position: 'relative'}),
                animate("250ms ease-in", keyframes([
                    style({top: 0}),
                    style({top: -300}),
                ]))
            ])
        ])
I am then importing it into my components. (animations: [customAnimation]
)
However, I'd like to use the new arguments features :
(http://sudheerjonna.com/blog/2017/06/30/angular-4-2-release-an-improved-version-for-animation-package/).
By instance, the -300 would become a parameter, and I would call it on me template elements by doing :
<div [@customAnimation]="{pixels: -300}">
Since I don't want to use animation() and useAnimation() as I want to use on specific dom element (not using a query() either) I simply didn't manage to do it. 
EDIT:
Got it working with :
export const leavingTowardsTop=
    trigger('leavingTowardsTop', [
        transition(':leave', [
            style({position: 'relative'}),
            animate("250ms ease-in", keyframes([
                style({top: 0}),
                style({top: "{{pixels}}"})
            ]))
        ], {params : { pixels: "-30px" }})
    ])
only issue, I can't specify another value than the default one (-30). I tried :
[@leavingTowardsTop]="{params : { pixels: '-300px' }}"
and
[@leavingTowardsTop]="{ pixels: '-300px' }"
I also tried not specifying the ' or px but it still takes 30px