RNDanovin/src/reducers/DefaultReducer.js

export function DefaultReducer(key, initialState = {}) {
  return (state = initialState, {type = '', payload = {}}) => {
    switch (type) {
      case key:
        return {...state, ...payload};
    }
    return state;
  };
}

export function buildAction(id) {
  return function(payload) {
    return {
      type: id,
      payload: payload,
    };
  };
}

export function buildActionForKey(id, key) {
  return function(payload) {
    let result = {
      type: id,
      payload: {},
    };
    result.payload[key] = payload;
    return result;
  };
}