扩展运算符上的语法错误，同时使用 babel env 预设

Question

我正在尝试通过将 babel es2015 和 stage-0 预设替换为 env 来“现代化”mern.io starter bolerplate。但是，env预设似乎无法识别client/modules/Intl/IntlReducer.js:9中的以下sn-p：

import { enabledLanguages, localizationData } from '../../../Intl/setup';
import { SWITCH_LANGUAGE } from './IntlActions';

const initLocale = global.navigator && global.navigator.language || 'en';

const initialState = {
  locale: initLocale,
  enabledLanguages,
  ...(localizationData[initLocale] || {}),
// ^ 
// SyntaxError: client/modules/Intl/IntlReducer.js: Unexpected token
};


const IntlReducer = (state = initialState, action) => {
  switch (action.type) {
    case SWITCH_LANGUAGE: {
      const { type, ...actionWithoutType } = action; // eslint-disable-line
      return { ...state, ...actionWithoutType };
    }

    default:
      return state;
  }
};

export default IntlReducer;

localizationData 对象填充到Intl/setup.js:56

这个扩展运算符对我来说似乎很正常，我无法发现语法错误。 此外，似乎该文件之前的其他代码正在被很好地转换，所以我猜 env 预设已正确应用。

这次失败的原因可能是什么？从 0 阶段到当前版本的 ES 是否不接受这种特殊风格的扩展运算符？我该如何进一步调查这个问题？

完整的错误信息（项目根路径被剥离）：

node_modules/babel-core/lib/transformation/file/index.js:590
      throw err;
      ^

SyntaxError: client/modules/Intl/IntlReducer.js: Unexpected token (9:2)
   7 |   locale: initLocale,
   8 |   enabledLanguages,
>  9 |   ...localizationData[initLocale]
     |   ^
  10 | };
  11 | 
  12 | const IntlReducer = (state = initialState, action) => {
    at Parser.pp$5.raise (node_modules/babylon/lib/index.js:4454:13)
    at Parser.pp.unexpected (node_modules/babylon/lib/index.js:1761:8)
    at Parser.pp$3.parseIdentifier (node_modules/babylon/lib/index.js:4332:10)
    at Parser.pp$3.parsePropertyName (node_modules/babylon/lib/index.js:4156:96)
    at Parser.parsePropertyName (node_modules/babylon/lib/index.js:6229:23)
    at Parser.pp$3.parseObj (node_modules/babylon/lib/index.js:4045:12)
    at Parser.pp$3.parseExprAtom (node_modules/babylon/lib/index.js:3719:19)
    at Parser.parseExprAtom (node_modules/babylon/lib/index.js:7238:22)
    at Parser.pp$3.parseExprSubscripts (node_modules/babylon/lib/index.js:3494:19)
    at Parser.pp$3.parseMaybeUnary (node_modules/babylon/lib/index.js:3474:19)
    at Parser.pp$3.parseExprOps (node_modules/babylon/lib/index.js:3404:19)
    at Parser.pp$3.parseMaybeConditional (node_modules/babylon/lib/index.js:3381:19)
    at Parser.pp$3.parseMaybeAssign (node_modules/babylon/lib/index.js:3344:19)
    at Parser.parseMaybeAssign (node_modules/babylon/lib/index.js:6474:20)
    at Parser.pp$1.parseVar (node_modules/babylon/lib/index.js:2340:24)
    at Parser.pp$1.parseVarStatement (node_modules/babylon/lib/index.js:2169:8)

Answer 1

对象传播尚未在规范中，目前处于第 3 阶段，这意味着 env 预设不会提供此功能。

如果你想在 Babel 中使用这个特性，你需要添加 babel-plugin-transform-object-rest-spread 转换。

您可以在这个 repo https://github.com/tc39/proposals查看 ES 提案的状态