The syntax would be:
var icon = (area == 1) ? icon1 : (area == 2) ? icon2 : icon0;
But this is starting to get complicated. You may well be better off just creating a function to do this work instead:
var icon = getIcon(area);
function getIcon(area) {
if (area == 1) {
return icon1;
} else if (area == 2) {
return icon2;
}
return icon0;
}