metamask-extension/app/scripts/migrations/031.js

// next version number
import { cloneDeep } from 'lodash';

const version = 31;

/*
 * The purpose of this migration is to properly set the completedOnboarding flag based on the state
 * of the KeyringController.
 */
export default {
  version,

  async migrate(originalVersionedData) {
    const versionedData = cloneDeep(originalVersionedData);
    versionedData.meta.version = version;
    const state = versionedData.data;
    const newState = transformState(state);
    versionedData.data = newState;
    return versionedData;
  },
};

function transformState(state) {
  const { KeyringController, PreferencesController } = state;

  if (KeyringController && PreferencesController) {
    const { vault } = KeyringController;
    PreferencesController.completedOnboarding = Boolean(vault);
  }

  return state;
}