[BUG] @snowpack/app-scripts-react is not compatible with Jest 27.

Bug Report Quick Checklist

• I am on the latest version of Snowpack & all plugins.
• I use package manager yarn
• I run Snowpack on OS Mac
• I run Snowpack on Node.js v12+

Describe the bug

@snowpack/app-scripts-react is not compatible with Jest 27.

TypeError: Cannot destructure property 'config' of 'cacheKeyOptions' as it is undefined.
    at Object.getCacheKey (/Users/piotr/[...]/node_modules/@snowpack/app-scripts-react/node_modules/babel-jest/build/index.js:217:14)
    at ScriptTransformer._getCacheKey (/Users/piotr/[...]/node_modules/@jest/transform/build/ScriptTransformer.js:280:41)
    at ScriptTransformer._getFileCachePath (/Users/piotr/[...]/node_modules/@jest/transform/build/ScriptTransformer.js:351:27)
    at ScriptTransformer.transformSource (/Users/piotr/[...]/node_modules/@jest/transform/build/ScriptTransformer.js:588:32)
    at revertHook.exts (/Users/piotr/[...]/node_modules/@jest/transform/build/ScriptTransformer.js:864:18)
    at Module._compile (/Users/piotr/[...]/node_modules/pirates/lib/index.js:93:29)
    at Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
    at Object.newLoader (/Users/piotr/[...]/node_modules/pirates/lib/index.js:104:7)
    at Module.load (internal/modules/cjs/loader.js:928:32)
    at Function.Module._load (internal/modules/cjs/loader.js:769:14)

Looks like the babel-jest dependency should be updated to 27.

Expected behavior

Tests cases should be executed.

[chphillipvose]

So I’ve forked locally to figure out a fix, and the package needs a couple of changes to work. The package.json file needs babel-jest updating to v27.x as per @pusewicz 's suggestion. But it also needs the createTransformer method updating (as per this issue in the Jest repo https://github.com/facebook/jest/issues/11444) which would look something like this:

packages/app-scripts-react/jest/babelTransform.js

// @remove-file-on-eject
/**
 * Copyright (c) 2014-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
'use strict'

const babelJestMd = require('babel-jest')
const importMetaBabelPlugin = require('./importMetaBabelPlugin')

const babelJest = babelJestMd.__esModule ? babelJestMd.default : babelJestMd

module.exports = babelJest.createTransformer({
  presets: ['babel-preset-react-app', '@babel/preset-react', '@babel/preset-typescript'],
  plugins: [[importMetaBabelPlugin]],
})

[RobertLowe]

This is the correct fix, jest and babel-jest should follow the same major, ex 27.x.x