freeCodeCamp/client/sagas/code-storage-saga.js

import store from 'store';

import types from '../../common/app/routes/challenges/redux/types';
import {
  savedCodeFound
} from '../../common/app/routes/challenges/redux/actions';
import {
  updateContents
} from '../../common/utils/polyvinyl';

const legacyPrefixes = [
  'Bonfire: ',
  'Waypoint: ',
  'Zipline: ',
  'Basejump: ',
  'Checkpoint: '
];
const legacyPostfix = 'Val';

function getCode(id) {
  if (store.has(id)) {
    return store.get(id);
  }
  return null;
}

function getLegacyCode(legacy) {
  const key = legacy + legacyPostfix;
  let code = null;
  if (store.has(key)) {
    code = '' + store.get(key);
    store.remove(key);
    return code;
  }
  return legacyPrefixes.reduce((code, prefix) => {
    if (code) {
      return code;
    }
    return store.get(prefix + key);
  }, null);
}

function legacyToFile(code, files, key) {
  return { [key]: updateContents(code, files[key]) };
}

export default function codeStorageSaga(actions$, getState) {
  return actions$
    .filter(({ type }) => (
      type === types.saveCode ||
      type === types.loadCode
    ))
    .map(({ type }) => {
      const {
        challengesApp: {
          id = '',
          files = {},
          legacyKey = '',
          key
        }
      } = getState();
      if (type === types.saveCode) {
        store.set(id, files);
        return null;
      }
      const codeFound = getCode(id);
      if (codeFound) {
        return savedCodeFound(codeFound);
      }
      const legacyCode = getLegacyCode(legacyKey);
      if (legacyCode) {
        return savedCodeFound(legacyToFile(legacyCode, files, key));
      }
      return null;
    });
}