immutable-update-with-key-or-index-or-function.js

type Query = string | number | (any) => boolean;
type Collection<T> = Array<T> | {[key: string]: Collection<T>};
type Mapper<T> = (T) => T;

function update<T: Collection<any>>(collection: T, queryList: Query[], mapper: Mapper<any>): T {
  const rootCollection = Array.isArray(collection) ? collection.slice() : _assign({}, collection);

  if (queryList.length === 0) {
    return mapper(rootCollection);
  } else {
    const query = queryList[0];
    let updateTarget;

    if (Array.isArray(rootCollection)) {
      let index: number = -1;
      if (typeof query === 'number') {
        updateTarget = rootCollection[query];
        index = query;
      } else if (typeof query === 'function') {
        updateTarget = _find(rootCollection, query);
        index = rootCollection.indexOf(updateTarget);
      } else {
        console.log(rootCollection, query); // eslint-disable-line no-console, ここは開発中に潰しきるべき箇所で、デバッグがめんどくさいところなので親切ログを出す
        throw new Error(`query type must be number or function for Array. '${typeof query}' was given`);
      }

      if (!updateTarget) {
        throw new Error(`target not found with '${query.toString()}'`);
      }

      rootCollection[index] = update(updateTarget, queryList.slice(1), mapper);
    } else {
      const key = query.toString();

      if (typeof query === 'string' || typeof query === 'number') {
        updateTarget = rootCollection[key];
        console.log(rootCollection, query); // eslint-disable-line no-console, ここは開発中に潰しきるべき箇所で、デバッグがめんどくさいところなので親切ログを出す
        throw new Error(`query type must be string or number for Obect. '${typeof query}' was given`);
      }

      if (!updateTarget) {
        throw new Error(`target not found with '${query.toString()}'`);
      }

      rootCollection[key] = update(updateTarget, queryList.slice(1), mapper);
    }


    return rootCollection;
  }
}