TableCache.js

// Cache should work in a way that it takes into consideration:
// 1. Page number and page size
// 2. Applied filters
// Other assumptions:
// 1. It should be stored for up to 5 minutes - for quick access (TODO: TBD)
// 2. It should use localStorage
import _ from 'lodash';
import moment from 'moment';
import LS from '../../../utils/localStorage'; // Available here https://gist.github.com/Ancinek/86d2c136a04c010811d295fb2fb2deab

const Cache = {
  cacheLSKey: 'tables-cache',
  defaultFilterHash: 'root',
  defaultReturnFromCache: { page: 0, pageSize: 0, data: [] },
  getFromCache(props = {}) {
    const {
      appliedFiltersHash = this.defaultFilterHash,
    } = props;
    const cache = LS.getItem(this.cacheLSKey, {});
    if (_.keys(cache).length === 0) {
      return this.defaultReturnFromCache;
    }
    const result = _.get(cache, `${appliedFiltersHash}`);
    if (!result) return this.defaultReturnFromCache;
    const { pageSize, data } = result;
    return {
      pageSize,
      page: parseFloat(_(data).keys().max()),
      data: _.keys(data).reduce((arr, page) => {
        const pageData = data[page] || [];
        return [...arr, ...pageData];
      }, []),
    };
  },
  storeInCache(props) {
    const {
      appliedFiltersHash = this.defaultFilterHash,
      page,
      pageSize,
      data = [],
    } = props;
    const cache = LS.getItem(this.cacheLSKey, {});
    if (!cache[appliedFiltersHash]) cache[appliedFiltersHash] = {};

    const currentTimestamp = moment().unix();
    const currentData = _.get(cache, `${appliedFiltersHash}.data`, {});
    const currentPageSize = _.get(cache, `${appliedFiltersHash}.pageSize`, {});

    const result = {
      lastSaveTimestamp: currentTimestamp,
      pageSize,
    };
    if (currentPageSize === pageSize) {
      result.data = {
        ...currentData,
        [page]: data,
      };
    } else {
      result.data = { [page]: data };
    }
    cache[appliedFiltersHash] = result;
    LS.setItem(this.cacheLSKey, cache);
    return LS.getItem(this.cacheLSKey);
  },
  clearCache() {
    LS.setItem(this.cacheLSKey, {});
  },
};

export default Cache;