How use RequireJS with web worker and sqlite3 with Node.js

i'm trying to import the sqlite3 library within a web worker using RequireJS, i'm using this library of sqlite3:

https://github.com/mapbox/node-sqlite3

i use this code, but doesn't work:

importScripts("../node_modules/requirejs/require.js");

console.log("before require");

require(
    {baseUrl:"/home/pi/node_modules/"},
    ["sqlite3"], function(sqlite3)
    {
        console.log("before db creation");
        this.db = new sqlite3.Database('MyDB.db');
        console.log("after db creation");

    }
);

this.onmessage = function(event) {

    ...
};

i create the web worker in this way:

var Worker = require('webworker-threads').Worker;
var worker= new Worker('myworker.js');

the result of the console log is this:

before require

and doesn't print anything else, how i can solve the problem?