tjc@example:~/example$ ls
index.ts  journal.ts  node_modules  package.json  package-lock.json
tjc@example:~/example$ cat journal.ts
export interface ISubgroupClassSubject {
  id: number;
  classId: number;
  subjectId: number;
  subgroupNumber: number;
}
tjc@example:~/example$ cat index.ts
import * as model from "./journal";

let subgroups: model.ISubgroupClassSubject[] = [];
console.log(subgroups.length);
tjc@example:~/example$ npx tsc index.ts
tjc@example:~/example$ node index.js
0
tjc@example:~/example$