Typescript @types/chai - how do you use Chai.Assertion?

I'm trying to use chai in typescript and I can't get any of the assertions to work as I would expect.

package.json

"dependencies": {
  "@types/chai": "^4.0.1",
  "@types/mocha": "^2.2.41",
  "chai": "^4.1.0",
  "mocha": "^3.4.2",
  "typescript": "2.4.2"
}

All of these emit compiler errors:

import * as chai from 'chai';
const expect = chai.expect;
const assert = chai.assert;

const expect = chai.expect;
expect(myVar).to.be.empty();
expect(myVar).to.be.empty;
expect(myVar).to.be.undefined();
expect(myVar).to.be.undefined;

If I try to import assertions directly - I don't see empty() as a valid assertion:

const assert = chai.assert;
assert.empty??? not there?

Any ideas are welcome.

Thanks - Chad

Quick answer

Shaun points out below - change the import to:

import { assert, expect } from 'chai';

Thanks Shaun