Changing border color based on method output


I have app with list of cards. Card has left border:

 .card-border {
    border-left: 6px solid;

<ion-card *ngFor="let routeJob of route.routeJobs" class="card-border"

I have method that returns name of the color specified in colors map at variables,scss. How can I bind my method output to border-color attribute?

<ion-card [style.border-color]="foo()">


Rapropos, thank you for reply. I tried this approach but somehow it didn’t work.
UPD Seems to be a problem with inaccessible sass variables in this way