import _extends from "@babel/runtime/helpers/esm/extends";
const enableStatistic = process.env.NODE_ENV !== 'production' || typeof CSSINJS_STATISTIC !== 'undefined';
let recording = true;
/**
 * This function will do as `Object.assign` in production. But will use Object.defineProperty:get to
 * pass all value access in development. To support statistic field usage with alias token.
 */
export function merge(...objs) {
  /* istanbul ignore next */
  if (!enableStatistic) {
    return _extends({}, ...objs);
  }
  recording = false;
  const ret = {};
  objs.forEach(obj => {
    const keys = Object.keys(obj);
    keys.forEach(key => {
      Object.defineProperty(ret, key, {
        configurable: true,
        enumerable: true,
        get: () => obj[key]
      });
    });
  });
  recording = true;
  return ret;
}
/** @private Internal Usage. Not use in your production. */
export const statistic = {};
/** @private Internal Usage. Not use in your production. */
// eslint-disable-next-line camelcase
export const _statistic_build_ = {};
/* istanbul ignore next */
function noop() {}
/** Statistic token usage case. Should use `merge` function if you do not want spread record. */
export default function statisticToken(token) {
  let tokenKeys;
  let proxy = token;
  let flush = noop;
  if (enableStatistic) {
    tokenKeys = new Set();
    proxy = new Proxy(token, {
      get(obj, prop) {
        if (recording) {
          tokenKeys.add(prop);
        }
        return obj[prop];
      }
    });
    flush = (componentName, componentToken) => {
      statistic[componentName] = {
        global: Array.from(tokenKeys),
        component: componentToken
      };
    };
  }
  return {
    token: proxy,
    keys: tokenKeys,
    flush
  };
}