Function getAggregateValue

src/common/aggregators.ts:76–118

(
  aggregateValue: AggregateValue | undefined,
  oldLength: number,
  newValues: IdMap<Value | undefined>,
  changedValues: Coll<[Value | undefined, Value | undefined]>,
  aggregators: Aggregators<Value, AggregateValue>,
  force = false,
)

  ]);

export const getAggregateValue = <Value, AggregateValue>(
  aggregateValue: AggregateValue | undefined,
  oldLength: number,
  newValues: IdMap<Value | undefined>,
  changedValues: Coll<[Value | undefined, Value | undefined]>,
  aggregators: Aggregators<Value, AggregateValue>,
  force = false,
) => {
  if (collIsEmpty(newValues)) {
    return undefined;
  }

  const [aggregate, aggregateAdd, aggregateRemove, aggregateReplace] =
    aggregators;
  force ||= isUndefined(aggregateValue);
  collForEach(changedValues, ([oldValue, newValue]) => {
    if (!force) {
      aggregateValue = isUndefined(oldValue)
        ? aggregateAdd?.(
            aggregateValue as AggregateValue,
            newValue as Value,
            oldLength++,
          )
        : isUndefined(newValue)
          ? aggregateRemove?.(
              aggregateValue as AggregateValue,
              oldValue,
              oldLength--,
            )
          : aggregateReplace?.(
              aggregateValue as AggregateValue,
              newValue,
              oldValue,
              oldLength,
            );
      force ||= isUndefined(aggregateValue);
    }
  });

  return force
    ? aggregate(collValues(newValues) as Value[], collSize(newValues))
    : aggregateValue;
};