4.0 alpha - TypeError: Cannot add property noFallthroughCasesInSwitch, object is not extensible

Created by: cktang88

Describe the bug

I updated a typescript CRA project (previously on ^3.4.0 react-scripts version) to use react-scripts "next" version to try out 4.0 alpha (following https://gist.github.com/iansu/282dbe3d722bd7231fa3224c0f403fa1), but encountered this error when running yarn start

yarn run v1.22.4
$ craco start
/Users/kwuang/github/suma-web/node_modules/react-scripts/scripts/utils/verifyTypeScriptSetup.js:210
        appTsConfig.compilerOptions[option] = suggested;
                                            ^

TypeError: Cannot add property noFallthroughCasesInSwitch, object is not extensible
    at verifyTypeScriptSetup (/Users/kwuang/github/suma-web/node_modules/react-scripts/scripts/utils/verifyTypeScriptSetup.js:210:45)
    at Object.<anonymous> (/Users/kwuang/github/suma-web/node_modules/react-scripts/scripts/start.js:31:1)
    at Module._compile (internal/modules/cjs/loader.js:1151:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1171:10)
    at Module.load (internal/modules/cjs/loader.js:1000:32)
    at Function.Module._load (internal/modules/cjs/loader.js:899:14)
    at Module.require (internal/modules/cjs/loader.js:1040:19)
    at require (internal/modules/cjs/helpers.js:72:18)
    at start (/Users/kwuang/github/suma-web/node_modules/@craco/craco/lib/cra.js:202:5)
    at Object.<anonymous> (/Users/kwuang/github/suma-web/node_modules/@craco/craco/scripts/start.js:27:1)
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

Did you try recovering your dependencies?

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Environment

Environment Info:

  current version of create-react-app: 3.4.1
  running from /Users/kwuang/github/suma-web/node_modules/create-react-app

  System:
    OS: macOS 10.15.3
    CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
  Binaries:
    Node: 13.7.0 - /usr/local/bin/node
    Yarn: 1.22.4 - /usr/local/bin/yarn
    npm: 6.13.6 - /usr/local/bin/npm
  Browsers:
    Chrome: 84.0.4147.105
    Firefox: 74.0.1
    Safari: 13.0.5
  npmPackages:
    react: ^16.13.1 => 16.13.1 (16.12.0)
    react-dom: ^16.13.1 => 16.13.1 (16.12.0)
    react-scripts: next => 4.0.0-next.77+3d74b79d
  npmGlobalPackages:
    create-react-app: Not Found

Steps to reproduce

(Write your steps here:)

1. change to next version of react-scripts in package.json
2. yarn to install new deps
3. yarn start

Expected behavior

Expected yarn start to work as before.

Actual behavior

Has console output (see above).

Reproducible demo

(Paste the link to an example project and exact instructions to reproduce the issue.)