RollupError: You have declared using "external" babelHelpers, but transforming index.js resulted in "inline".

[JinHe-PerkinElmer]

• Rollup Plugin Name: @rollup/plugin-babel
• Rollup Plugin Version: "^6.0.3"
• Rollup Version: "^3.26.3"
• Operating System (or Browser): Win10 - Google Chrome Version 114.0.5735.199
• Node Version: v14.21.3
• Link to reproduction (⚠️ read below):

Expected Behavior

Solve the error about "external" babelHelpers and build successful.

Actual Behavior

[!] (plugin commonjs--resolver) RollupError: You have declared using "external" babelHelpers, but transforming C:\Documents\GitHub\OneSource-Web-CommonLib\React\index.js resulted in "inline". Please check your configuration.

Additional Information

Background: We used "rollup": "^0.64.1" before, Now to do technical upgrades, I upgrade rollup to the latest version v3, also update babels and plugins. But now meet this error. Can some one help this?

Here is the rollup.config:

import { babel } from '@rollup/plugin-babel';
import commonjs from '@rollup/plugin-commonjs';
import external from 'rollup-plugin-peer-deps-external';
import postcss from 'rollup-plugin-postcss';
import { nodeResolve } from '@rollup/plugin-node-resolve';
import url from '@rollup/plugin-url';
import svgr from '@svgr/rollup';

import pkg from './package.json';

{
  input: 'index.js',
  output: [
    {
      file: pkg.main,
      format: 'cjs',
      sourcemap: true,
    },
    {
      file: pkg.module,
      format: 'es',
      sourcemap: true,
    },
  ],
  plugins: [
    external(),
    postcss({
      extract: 'dist/os-common.css',
    }),
    url(),
    svgr(),
    commonjs(),
    babel({
      exclude: 'node_modules/**',
      babelHelpers: 'external',
    }),
    nodeResolve(),
  ],
}

[JinHe-PerkinElmer]

I made some changes to solve errors above:

1. add @babel/plugin-external-helpers into plugins list of .babelrc;
2. Adjust order of rollup plugins: place commonjs() after babel()
   Then I can build my lib normally. But I face another problem:
   I find all babel helpers in resulting dist/indes.es.js, like babelHelpers.classCallCheck; babelHelpers.createClass and so on. All helpers only have references but no definitions. It's very confusing. @tjenkinson Can you help? thank.

[JinHe-PerkinElmer]

Finally, @babel/plugin-transform-runtime solves babelHelpers referencing issues.