deathmtn

Ah, that last snippet I posted provided a default argument for the entire object. Here's what you need for defaults for values in that object:

export function getNByNGraph(
  { points, startProp = 'from', destProp = 'to', distProp = 'weight' } :
  { points: IdPt[]; startProp?: string; destProp?: string; distProp?: string } 
): IdPt[] {

Woe to thee if you try to intuit syntax here.