I forked angular repo from remote to my local system then run yarn install gives the following error

[orchid siren]

$ ts-node --esm --project scripts/tsconfig.json scripts/build/build-packages-dist.mts
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".mts" for /media/karimul/6C4EE18D4EE1507E/open source/angular/scripts/build/build-packages-dist.mts

[true locust]

Does your tsconfig have it's module and moduleResolution set to NodeNext? What version of Node are you using?

[orchid siren]

yarn version v1.22.19
Node.js v20.11.0

As mentioned in package.json
"engines": {
"node": "^18.13.0 || ^20.9.0",
"yarn": ">=1.22.4 <2",
"npm": "Please use yarn instead of NPM to install dependencies"
},

and i just follow the instructions from angular team :

Getting the Sources

Fork and clone the Angular repository:

1. Login to your GitHub account or create one by following the instructions given
   here.
2. Fork the main Angular
   repository.
3. Clone your fork of the Angular repository and define an upstream remote pointing back to
   the Angular repository that you forked in the first place.

# Clone your GitHub repository:
git clone [email protected]:<github username>/angular.git

# Go to the Angular directory:
cd angular

# Add the main Angular repository as an upstream remote to your repository:
git remote add upstream https://github.com/angular/angular.git

Installing NPM Modules

Next, install the JavaScript modules needed to build and test Angular:

# Install Angular project dependencies (package.json)
yarn install

Building

To build Angular run:

yarn build

• Results are put in the dist/packages-dist folder.

[true locust]

And are you actually meaning to contribute back to the core Angular repository? I hate to double check, but you aren't just trying to make an Angular frontend?

[mint wolf]

Did you run the postinstall script prior to running the build script?

[orchid siren]

No ... first run yarn install then build

$ ts-node --esm --project scripts/tsconfig.json scripts/build/build-packages-dist.mts
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".mts" for /media/karimul/6C4EE18D4EE1507E/open source/angular/scripts/build/build-packages-dist.mts

[mint wolf]

Ok, could you run yarn postinstall and then try yarn build again

[orchid siren]

why this happen again TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".mts" for ???

$ ts-node --esm --project scripts/tsconfig.json scripts/build/build-packages-dist.mts

why .mts file extension not supporting which is located in script folder ??

[mint wolf]

I googled a bit and it seems that node 20 introduced a breaking change that causes this error. Could you try to downgrade to node 18 and try?
see https://github.com/nodejs/node/issues/48257 and https://github.com/TypeStrong/ts-node/issues/1997