Function primaryDimensionFor

scripts/declared-annotation.ts:87–106

(signalKey: string)

 * Returns null if the signal_key isn't in the map.
 */
export function primaryDimensionFor(signalKey: string): Dimension | null {
  const entry = SIGNAL_MAP[signalKey];
  if (!entry) return null;
  const totals: Partial<Record<Dimension, number>> = {};
  for (const choice of Object.keys(entry)) {
    for (const dd of entry[choice]) {
      totals[dd.dim] = (totals[dd.dim] ?? 0) + Math.abs(dd.delta);
    }
  }
  let best: Dimension | null = null;
  let bestVal = -Infinity;
  for (const d of ALL_DIMENSIONS) {
    const v = totals[d] ?? 0;
    if (v > bestVal) {
      bestVal = v;
      best = d;
    }
  }
  return bestVal > 0 ? best : null;
}

/**
 * Given a signal_key, return a one-line plain-English annotation when