add import sideEffect plugin for babel, work for antd.

{"libraryName": "antd", "sideEffect", { "Button": "/projj/a/c/button.less" }}

import { Button } from 'antd';
      ↓ ↓ ↓ ↓ ↓ ↓
import { Button } from 'antd';
import '/projj/a/c/button.less';

npm install babel-plugin-import-sideeffect --save-dev

Via .babelrc or babel-loader

{
  "plugins": [["import-sideeffect", options]]
}

sideEffect can be object, each key would match import object where from libraryName.

{
  "libraryName": "antd",
  "sideEffect": {}
}

sideEffect can be function, return your custom path.

{
  "libraryName": "antd",
  "sideEffect": (name, file) => {}
}