ts-node+mocha+esm+@types

package.json

{
  "name": "mocha-ts-node",
  "type": "module",
  "scripts": {
    "test": "mocha test.ts"
  },
  "dependencies": {
    "@rdfjs/term-set": "2.0.1",
    "@types/mocha": "9.1.1",
    "@types/rdfjs__term-set": "2.0.0",
    "mocha": "9.2.2",
    "ts-node": "10.8.0",
    "typescript": "4.6.4"
  },
  "mocha": {
    "loader": "ts-node/esm",
    "extension": [
      "ts"
    ]
  }
}

test.ts

import {describe, it} from 'mocha'
import * as assert from 'assert'
import TermSet from '@rdfjs/term-set'

describe('TermSet', () => {
    it('should be defined', () => {
        assert.ok(TermSet)
    })
})

tsconfig.json

{
  "compilerOptions": {
    "target": "ES2019",
    "module": "ESNext",
    "moduleResolution": "Node",
    "esModuleInterop": true,
    "declaration": true
  }
}