I have npm package which both can be imported in other projects and also be used as a CLI. To do this, I have 2 option configurations:

export default defineConfig(() => [
  {
    entry: {
      lib: './src/index.ts',
    },
  },
  {
    entry: {
      cli: './src/cli.ts',
    },
  },
]);

However, this warns about the TS2345 error. Basically, it is expecting both the entry objects to have same keys. Since I added lib in first one, it is expecting that I add it to the second one as well and same for cli.

If I add a @ts-ignore comment, tsup works as expected and generates the desired outputs.

Also, creating the options object outside of the array fixes the issue:

const op1: Options = {
    entry: {
      lib: './src/index.ts',
    },
  }

const op2: Options = {
  entry: {
    cli: './src/cli.ts',
  },
}

export default defineConfig(() => [
  op1,
  op2,
]);