Merge Query Strings (Node.js)

merge-querystrings.js

const url = require('url')

const appendQueryString = (url_string, query_string_object) => {
  const parsed_url = url.parse(url_string, true);
  parsed_url.query = Object.assign(
    parsed_url.query,
    query_string_object,
  );
  return url.format(parsed_url);
};