Constructor is not called during instantiation of imported class

When I was trying to write some unit tests for ECMAScript6 class, I encoutered following problem: constructor is not being called during imported class instantiation.

I quickly found out that it is some behaviour of Babel + node.js I just can't understand. Here is the smallest piece of code showing the problem:

// dummy.js
export class Dummy {
    construct(){
        this.value = 1
    }
    set(value){
        this.value = value
    }
}

 

// main.js
require("babel-register")({
    presets: [
        "es2015" 
    ],
});

var Dummy = require('./dummy.js').Dummy

var d = new Dummy()
console.log(d.value) // undefined, should be 1

d.set(13)
console.log(d.value) // 13

It really confuses me, because method set() works as expected. Originally I got such weird behaviour with ES6 import statement, however I couldn't use it here as node.js does not support it. As You can see we get the same problem with require.

I use node v6.10 and babel v6.24.

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