How to fix tsc command expects a TypeScript file in TypeScript

Run the compiler initialization tool to scratch a tsconfig in the folder where you expect to build from:

npx tsc --init

If the project already has a configuration file, make sure you run tsc from the directory that contains that tsconfig or explicitly pass its path with tsc -p path/to/tsconfig.json.

You can compile individual files without a config by giving them on the CLI:

npx tsc src/index.ts src/lib/util.ts

Use .ts, .tsx, .cts, or .mts extensions and avoid directories or JavaScript-only files so that the compiler sees valid input.

TypeScript walks up from your current working directory to find a tsconfig.json. If you operate inside a subfolder, change into the parent or tell the compiler exactly where the config lives:

cd packages/widget
npx tsc
# or
npx tsc -p ../tsconfig.base.json

This ensures the compiler does not exit before reading compiler options.

If the repository only contains JavaScript and you rely on allowJs, flip on the compiler option or add TypeScript files so the input set is not empty:

{
  "compilerOptions": {
    "allowJs": true,
    "include": ["src/**/*"]
  }
}

Otherwise, add a .ts entry (even an empty shim) to give tsc something to compile.

Check npm scripts, CI tasks, and IDE pre-launch commands so they change into the right folder or pass the -p flag. A script that calls npx tsc before building the workspace might run in the repo root while the tsconfig lives in packages/app. Adjust the command or script to match the project layout.