old_contents: /**
   * migrate.js
   */
  
  import {
    getStorage, removeStorage, updateCommand,
  } from "./browser.js";
  
  /* constants */
  import {EDITOR_EXEC, OPTIONS_OPEN} from "./constant.js";
  const KEY_ACCESS = "accessKey";
  const KEY_EDITOR = "editorShortCut";
  const KEY_OPTIONS = "optionsShortCut";
  
  /**
   * migrate old storage
   * @returns {Promise.<Array>} - results of each handler
   */
  export const migrateStorage = async () => {
    const store = await getStorage([
      EDITOR_EXEC,
      KEY_ACCESS,
      KEY_EDITOR,
      KEY_OPTIONS,
      OPTIONS_OPEN,
    ]);
    const func = [];
    if (store[EDITOR_EXEC]) {
      const {value} = store[EDITOR_EXEC];
      await updateCommand(EDITOR_EXEC, value);
      func.push(removeStorage(EDITOR_EXEC));
    }
    if (store[OPTIONS_OPEN]) {
      const {value} = store[OPTIONS_OPEN];
      await updateCommand(OPTIONS_OPEN, value);
      func.push(removeStorage(OPTIONS_OPEN));
    }
    if (store[KEY_ACCESS]) {
      func.push(removeStorage(KEY_ACCESS));
    }
    if (store[KEY_EDITOR]) {
      func.push(removeStorage(KEY_EDITOR));
    }
    if (store[KEY_OPTIONS]) {
      func.push(removeStorage(KEY_OPTIONS));
    }
    return Promise.all(func);
  };
  
new_contents: /**
   * migrate.js
   */
  
  import {
    getAllStorage, removeStorage, updateCommand,
  } from "./browser.js";
  
  /* constants */
  import {EDITOR_EXEC, OPTIONS_OPEN} from "./constant.js";
  const ENABLE_PB = "enablePB";
  const KEY_ACCESS = "accessKey";
  const KEY_EDITOR = "editorShortCut";
  const KEY_OPTIONS = "optionsShortCut";
  
  /**
   * migrate old storage
   * @returns {Promise.<Array>} - results of each handler
   */
  export const migrateStorage = async () => {
    const store = await getAllStorage();
    const func = [];
    if (store[EDITOR_EXEC]) {
      const {value} = store[EDITOR_EXEC];
      await updateCommand(EDITOR_EXEC, value);
      func.push(removeStorage(EDITOR_EXEC));
    }
    if (store[OPTIONS_OPEN]) {
      const {value} = store[OPTIONS_OPEN];
      await updateCommand(OPTIONS_OPEN, value);
      func.push(removeStorage(OPTIONS_OPEN));
    }
    if (store[ENABLE_PB]) {
      func.push(removeStorage(ENABLE_PB));
    }
    if (store[KEY_ACCESS]) {
      func.push(removeStorage(KEY_ACCESS));
    }
    if (store[KEY_EDITOR]) {
      func.push(removeStorage(KEY_EDITOR));
    }
    if (store[KEY_OPTIONS]) {
      func.push(removeStorage(KEY_OPTIONS));
    }
    return Promise.all(func);
  };
  
subject: Update migrate.js