ahmadnassri/httpsnippet

export type ReducedHelperObject = Record<string, string[] | string>;

export const reducer = <T extends { name: string; value: string }>(
  accumulator: ReducedHelperObject,
  pair: T,
) => {
  const currentValue = accumulator[pair.name];
  if (currentValue === undefined) {
    accumulator[pair.name] = pair.value;
    return accumulator;
  }

  // If we already have it as array just push the value
  if (Array.isArray(currentValue)) {
    currentValue.push(pair.value);
    return accumulator;
  }

  // convert to array since now we have more than one value for this key
  accumulator[pair.name] = [currentValue, pair.value];
  return accumulator;
};