How to enable optional chaining with Create React App and TypeScript

问题

Support for the experimental syntax 'optionalChaining' isn't currently enabled

I was getting the above error. I followed this post and added "@babel/plugin-proposal-optional-chaining": "^7.7.4" into my devDependencies.

Then I am getting this error,

Add @babel/plugin-proposal-optional-chaining (https://git.io/vb4Sk) to the 'plugins' section of your Babel config to enable transformation.

So I followed this post and added .babelrc file into my project's root

{
    "presets": ["react", "es2015","stage-1"],
    "plugins": ["transform-runtime", "transform-optional-chaining"]
}

This did not seem to do anything. I also heard someone mentioning that Create React App does not let you modify babel's configurations. So my question is how can I enable optional chaining without re-wiring the whole CRA?

P.S. I am using "typescript": "^3.7.2", or at least that is what my package.json says. I tried npm install to ensure it is updated. Not sure if CRA doing something weird underneath and using older version of TypeScript somehow.

EDIT: When I started the project with CRA, I believe we were using TypeScript: 3.6.x. I wanted to use Optional Chaining, so I changed my package.json file to "typescript": "^3.7.2" then npm install. I think the problem is, TypeScript knows that I am using 3.7.2, but CRA still have older configuration and I am not sure how I can update that.

回答1:

Create-React-App uses babel to transpile the TypeScript so it isn't using your npm installed version of TypeScript. Version 3.3.0 of react-scripts supports TypeScript 3.7. You can install it and use it with:

yarn add react-scripts@3.3.0

-or-
npm install -s react-scripts@3.3.0

回答2:

React scripts 3.3.0 and above supports it. There is no need to install the react-scripts@next.

Just put in the package.json "react-scripts": "^3.3.0" and it will work.

回答3:

package.json

{
  "scripts": {
    "start": "react-app-rewired start",
    "build": "react-app-rewired build",
    "test": "react-app-rewired test --env=jsdom"
  },
  "devDependencies": {
    "@babel/plugin-proposal-optional-chaining": "^7.2.0",
    "customize-cra": "^0.4.1",
    "react-app-rewired": "^2.1.3"
  }
  ...other
}

config-overrides.js

const { useBabelRc, override } = require('customize-cra');
module.exports = override(useBabelRc());

.babelrc

{
  "plugins": ["@babel/plugin-proposal-optional-chaining"]
}

detailed blogpost

来源：https://stackoverflow.com/questions/59093630/how-to-enable-optional-chaining-with-create-react-app-and-typescript

标签

typescript

babel

create-react-app