TypeError: Cannot assign to read only property 'jsx' of object '#<Object>'

[aadityarajkumawat]

Describe the bug

When creating a react-typescript app using

npx create-react-app . --template typescript

The error:

yarn run v1.22.5
$ react-scripts start
/home/aditya/all/yt/twitter/node_modules/react-scripts/scripts/utils/verifyTypeScriptSetup.js:239
      appTsConfig.compilerOptions[option] = value;
                                          ^

TypeError: Cannot assign to read only property 'jsx' of object '#<Object>'
    at verifyTypeScriptSetup (/home/aditya/all/yt/twitter/node_modules/react-scripts/scripts/utils/verifyTypeScriptSetup.js:239:43)
    at Object.<anonymous> (/home/aditya/all/yt/twitter/node_modules/react-scripts/scripts/start.js:31:1)
    at Module._compile (internal/modules/cjs/loader.js:778:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)
    at Module.load (internal/modules/cjs/loader.js:653:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
    at Function.Module._load (internal/modules/cjs/loader.js:585:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:831:12)
    at startup (internal/bootstrap/node.js:283:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:623:3)
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[roderik]

I have this happening after upgrading to typescript 4.1

[maltoze]

Duplicate with #9868

[convexhull]

Same issue I am facing. Just ran the npx create-react-app my-app --template typescript command.
When I run it using yarn start, I get this error.

[LiuJun0]

+1
Me too.

[n1ru4l]

Duplicate of #9868

[NathanScott85]

Definitely, a Duplicate of #9868 but also can confirm getting the following error: -

TypeError: Cannot assign to read only property 'jsx' of object '#<Object>'
    at verifyTypeScriptSetup (/Users/Nathan/Projects/pwa/pwa-react/pwa-react/node_modules/react-scripts/scripts/utils/verifyTypeScriptSetup.js:239:43)
    at Object.<anonymous> (/Users/Nathan/Projects/pwa/pwa-react/pwa-react/node_modules/react-scripts/scripts/start.js:31:1)
    at Module._compile (internal/modules/cjs/loader.js:1156:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1176:10)
    at Module.load (internal/modules/cjs/loader.js:1000:32)
    at Function.Module._load (internal/modules/cjs/loader.js:899:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:74:12)
    at internal/main/run_main_module.js:18:47
error Command failed with exit code 1.

[grug]

+1 seeing this as well

[LenChang]

+1 Now i can't create new typescript anymore !!!

[ChristianIvicevic]

You can fix this issue for the time being by downgrading to Typescript 4.0.5. It is an issue with Typescript 4.1+ being present with CRA 4.0 and may be fixed once CRA 4.0.1 is released.

[dnepro]

I've just had this exact error, the problem is increate-react-app\packages\react-scripts\scripts\utils\verifyTypeScriptSetup.js on Line 151 (to find it search for ts.JsxEmit.ReactJ) it was using ts.JsxEmit.ReactJsx but should use ts.JsxEmit.ReactJSX (JSX being upper case)

Thanks to @benneq this is fixed in the master branch (already three weeks ago), just needs a new patch version (see the fix: #9869).
Can somebody release a 4.0.1?

[convexhull]

You can fix this issue for the time being by downgrading to Typescript 4.0.5. It is an issue with Typescript 4.1+ being present with CRA 4.0 and may be fixed once CRA 4.0.1 is released.

I tried that. Downgraded to TS 4.0.5 and replace "react-jsx" with "react" in the tsconfig.json jsx field.
But nothing seems to solve this.

[neonise]

please solve this . i have this error too.