Manual parts list: quantities and mass

export function rows(m, meshes, { view = null, scope = 'all', collapse = true } = {}) {
  const shown = scope === 'view' ? new Set(shownInstances(m, view).filter((i) => !view?.insts?.[i.id]?.ghost).map((i) => i.id)) : null;
  const insts = m.instances.filter((i) => !shown || shown.has(i.id));
  const out = [];
  const byKey = new Map();
  for (const inst of insts) {
    const p = m.parts[inst.part];
    let r = null;
    if (collapse) {
      r = byKey.get(inst.part);
      if (!r) r = out.find((x) => x.pids[0] !== inst.part && (p.number ? x.number === p.number : !x.number && x.name === p.name) && sameShape(meshes.get(x.pids[0]), meshes.get(inst.part)));
    }
    if (!r) {
      const vol = statsOf(meshes.get(inst.part)).volume;
      r = { item: numberOf(m, inst.part), qty: 0, pids: [inst.part], insts: [], number: p.number, name: p.name, description: p.description, material: p.material, density: p.density, volume: vol, massEach: vol !== null && p.density ? vol * p.density / 1000 : null, massTotal: null, props: { ...p.props } };
      out.push(r);
    } else if (!r.pids.includes(inst.part)) { r.pids.push(inst.part); if (r.item === null) r.item = numberOf(m, inst.part); }
    if (collapse) byKey.set(inst.part, r);
    r.qty++; r.insts.push(inst.id);
  }
  for (const r of out) r.massTotal = r.massEach === null ? null : r.massEach * r.qty;
  return out.sort((a, b) => (a.item ?? Infinity) - (b.item ?? Infinity) || a.name.localeCompare(b.name));
}

/** Is the shape of two parts the same (corners and triangles, within a hair)? */
function sameShape(a, b) {
  if (!a || !b || a.positions.length !== b.positions.length || a.indices.length !== b.indices.length) return false;
  const sa = statsOf(a), sb = statsOf(b);
  return Math.abs(sa.volume - sb.volume) <= 1e-6 * Math.max(sa.volume, 1) && Math.abs(sa.area - sb.area) <= 1e-6 * Math.max(sa.area, 1);
}

const n3 = (v) => (v === null || v === undefined ? '' : String(Number(v.toFixed(3))));
const mass = (g) => (g === null ? '' : g >= 1000 ? String(Number((g / 1000).toFixed(3))) + ' kg' : String(Number(g.toFixed(2))) + ' g');