Angular 4 Animations add parameters

Here is the solution I needed

[@leavingTowardsTop]="{value: ':leave', params : {topPixels: '-300px'}}"

You need to parameterize the top style like so:

export const customAnimation=
    trigger('customAnimation', [
        transition(':leave', [
            animate("500ms ease-in", keyframes([
                style({'margin-top': "-{{pixels}}px", 'height': "{{pixels}}px", 'margin-bottom': "0px"}),
            ]))
        ], {params : { pixels: "30" }})
    ]);

Then call it in the view like so:

[@customAnimation]="{value: ':leave', params: { pixels: 100}}"

Demo