How to pass babel transpiling to mocha?

[christian-schwaderer]

I have a mixed JavaScript/TypeScript project. For running, the JavaScript files are getting transpiled via babel-node.

Now, I'm trying to set-up ts-mocha for running tests. However, I keep getting

src/index.js:3

import 'whatever';

^^^^^^

SyntaxError: Cannot use import statement outside a module

I guess, I would need to pass something like --compilers js:@babel/register to mocha. But how do I do that when using ts-mocha?