可選鏈在 create-react-app 中不起作用

Question

在create-react-app項目中，我在 `.babelrc 中使用@babel/plugin-proposal-optional-chaining

但是，我有這個錯誤： Module parse failed: Unexpected token (22:16) You may need an appropriate loader to handle this file type.

這是我所有的 babel 依賴項：

{
  "dependencies": {
    "@babel/core": "^7.9.0",
    "@babel/node": "^7.8.7",
    "@babel/plugin-external-helpers": "^7.8.3",
    "@babel/plugin-proposal-class-properties": "^7.8.3",
    "@babel/plugin-proposal-decorators": "^7.8.3",
    "@babel/plugin-proposal-json-strings": "^7.8.3",
    "@babel/plugin-proposal-object-rest-spread": "^7.9.5",
    "@babel/plugin-proposal-optional-chaining": "^7.9.0",
    "@babel/plugin-syntax-dynamic-import": "^7.8.3",
    "@babel/plugin-syntax-import-meta": "^7.8.3",
    "@babel/plugin-transform-async-to-generator": "^7.8.3",
    "@babel/plugin-transform-modules-commonjs": "^7.9.0",
    "@babel/plugin-transform-react-constant-elements": "^7.9.0",
    "@babel/plugin-transform-react-inline-elements": "^7.9.0",
    "@babel/plugin-transform-runtime": "^7.9.0",
    "@babel/polyfill": "^7.8.7",
    "babel-plugin-add-module-exports": "^1.0.2",
    "babel-plugin-array-includes": "^2.0.3",
    "babel-plugin-inline-react-svg": "^1.1.1"
  }
}

• 節點 v14.0.0
• npm 6.14.4
• 反應腳本 2.1.8

為了讓它工作，我還需要什么？

Answer 1

你只需要確保你已經安裝了react-scripts 3.3.0+版本，因為它已經內置了可選的鏈接：

const obj = { a: `Hello` };

// Hello World
const App = () => {
  return (
    <>
      {obj?.a}
      {obj?.b ?? ` World`}
    </>
  );
};