src/Ass.js
function subKeepAssigned(objs, k, pusher) {
  var ka = keepAssigned();
  objs
    .map(propGetter(k))
    .filter(Boolean)
    .forEach(o => _keepAssigned(ka, o, pusher));
  return ka;
}
function subKeepAssigned(objs, k, pusher) {
  var ka = keepAssigned();
  objs
    .map(propGetter(k))
    .filter(Boolean)
    .forEach(o => _keepAssigned(ka, o, pusher));
  return ka;
}
function subKeepAssigned ( objs , k , pusher ) { var ka = keepAssigned ( ) ; objs . map ( propGetter ( k ) ) . filter ( Boolean ) . forEach ( o => _keepAssigned ( ka , o , pusher ) ) ; return ka ; }
Make a keepAssigned object for subobjects with some key.
Make a keepAssigned object for subobjects with some key .