How to use optionalDependencies with import/export?

How can I use optionalDependencies with import/export syntax?

Specifically, the example they give on npmjs.org shows:

try {
  var foo = require('foo')
  var fooVersion = require('foo/package.json').version
} catch (er) {
  foo = null
}

But import won't work inside a try block. What's the recommended way to conditionally require modules using ES6-modules syntax?

via mpen