Duplicate identifier 'URL'.

[onlydave]

Failed to compile.

/apps/my-app/node_modules/@types/node/index.d.ts
(2381,15): Duplicate identifier 'URL'.

Environment

react-scripts-ts@2.15.1
npm -v 6.0.0 (tried @4 too)
node -v v8.11.1

create-react-app my-app --scripts-version=react-scripts-ts
cd my-app
npm start

Then got the error above

├── @types/jest@22.2.3
├── @types/node@10.0.0
├─┬ @types/react@16.3.12
│ └── csstype@2.4.1
├─┬ @types/react-dom@16.0.5
│ ├── @types/node@10.0.0 deduped
│ └── @types/react@16.3.12 deduped

[onlydave]

Changing @types/node to version ^7.0.21 works. I'll do some trial and error to see if a more recent version works but might not be safe to let create app use the latest version

├── @types/jest@22.2.3
├── @types/node@7.0.61
├─┬ @types/react@16.3.12
│ └── csstype@2.4.1
├─┬ @types/react-dom@16.0.5
│ ├── @types/node@7.0.61 deduped
│ └── @types/react@16.3.12 deduped

---

EDIT: "@types/node": "^9.6.7" works 👍 🎉

├── @types/jest@22.2.3
├── @types/node@9.6.7
├─┬ @types/react@16.3.12
│ └── csstype@2.4.1
├─┬ @types/react-dom@16.0.5
│ ├── @types/node@9.6.7 deduped
│ └── @types/react@16.3.12 deduped

[ajgassner]

Same here. Windows 10, node v 10.0.0, npm 4.6.1

[azu]

Related DefinitelyTyped/DefinitelyTyped#25342

[webstar1208]

Great Thanks. It works on V9.6.7.
But I have some questions.
I just searched Node previous version but not found 9.6.7.
What 's happened?

[Guria]

Node JS 10.0 according to release notes introduces URL as new global

[Guria]

So, now it conflicts with typescript lib.d.ts files. And this issue completely unrelated to current repo.
I would recommend to try using typeRoots setting in tsconfig and list only specific node_modules/@types/... needed for you project

[dereke55]

Probably a noob question/issue here, but is there a workaround in the meantime? Attempting to downgrade to @types/node@9.6.7 as suggested didn't seem to work:

$ npx create-react-app test-app  --scripts-version=react-scripts-ts
$ cd test-app
$ npm i @types/node@9.6.7
$ yarn start

output:

yarn run v1.6.0
$ react-scripts-ts start
/bin/sh: react-scripts-ts: command not found
error Command failed with exit code 127.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[zeljkoantich]

@dereke55 you must target devDependencies with the "-D" flag:

npm remove -D @types/node  
npm i -D @types/node@9.6.7

[aditya-goyal-github]

Thanks @GoodDay2You , it works for me, all duplicate errors gone.

[yajuve]

I updated version to
npm i @types/node@9.6.7
and it works

[HuangHongRui]

Thanks..man
It Works for me..

npm i @types/node@9.6.7

[onlydave]

Depends on your version of npm maybe it might not downgrade if you've already got 10.0.0 installed.

The safest thing to do is probably to edit package.json and change @types/node there.
Then rm -rf node_modules and then npm i

[dereke55]

Thanks again @GoodDay2You , worked like a charm

[DorianGrey]

FYI:
I've added a commit to pin the @types/node for the moment (though this is not yet released).
10b727f

However, this might no longer be required regarding this comment:
DefinitelyTyped/DefinitelyTyped#25356 (comment)
The issue with @types/node should be fixed with version 10.0.1. Could you give this version a try (just manually update it) ?