Bin/webpack error Cannot find package '@babel/plugin-proposal-private-methods'

Related:

Noting for posterity:

Using jets version 4.0.1, though the issue not related to the jets version. It’s a node version with babel and the babel.config.js that jets webpacker:install installs issue. Believe babel updated the interface and the babel.config.js needs to be updated to reflect that.

To reproduce:

jets new demo
cd demo
bin/webpack

Details:

$ bin/webpack
node:internal/process/promises:279
            triggerUncaughtException(err, true /* fromPromise */);
            ^

Error: Cannot find package '@babel/plugin-proposal-private-methods' imported from ~/demo/babel-virtual-resolve-base.js
    at new NodeError (~/demo/node_modules/@babel/core/lib/vendor/import-meta-resolve.js:203:5)
    at packageResolve (~/demo/node_modules/@babel/core/lib/vendor/import-meta-resolve.js:873:9)
    at moduleResolve (~/demo/node_modules/@babel/core/lib/vendor/import-meta-resolve.js:902:20)
    at defaultResolve (~/demo/node_modules/@babel/core/lib/vendor/import-meta-resolve.js:985:15)
    at resolve (~/demo/node_modules/@babel/core/lib/vendor/import-meta-resolve.js:999:12)
    at resolve (~/demo/node_modules/@babel/core/lib/config/files/import-meta-resolve.js:13:10)
    at tryImportMetaResolve (~/demo/node_modules/@babel/core/lib/config/files/plugins.js:137:45)
    at resolveStandardizedNameForImport (~/demo/node_modules/@babel/core/lib/config/files/plugins.js:159:19)
    at resolveStandardizedName (~/demo/node_modules/@babel/core/lib/config/files/plugins.js:168:12)
    at loadPlugin (~/demo/node_modules/@babel/core/lib/config/files/plugins.js:47:20)
    at loadPlugin.next (<anonymous>)
    at createDescriptor (~/demo/node_modules/@babel/core/lib/config/config-descriptors.js:139:16)
    at createDescriptor.next (<anonymous>)
    at step (~/demo/node_modules/gensync/index.js:261:32)
    at evaluateAsync (~/demo/node_modules/gensync/index.js:291:5)
    at ~/demo/node_modules/gensync/index.js:44:11
    at Array.forEach (<anonymous>)
    at Function.async (~/demo/node_modules/gensync/index.js:43:15)
    at Function.all (~/demo/node_modules/gensync/index.js:216:13)
    at Generator.next (<anonymous>)
    at createDescriptors (~/demo/node_modules/@babel/core/lib/config/config-descriptors.js:101:41)
    at createDescriptors.next (<anonymous>)
    at createPluginDescriptors (~/demo/node_modules/@babel/core/lib/config/config-descriptors.js:98:17)
    at createPluginDescriptors.next (<anonymous>)
    at ~/demo/node_modules/@babel/core/lib/gensync-utils/functional.js:21:23
    at Generator.next (<anonymous>)
    at mergeChainOpts (~/demo/node_modules/@babel/core/lib/config/config-chain.js:347:34)
    at mergeChainOpts.next (<anonymous>)
    at chainWalker (~/demo/node_modules/@babel/core/lib/config/config-chain.js:314:14)
    at chainWalker.next (<anonymous>) {
  code: 'ERR_MODULE_NOT_FOUND'
}