How to generate an API request if some of the parameters are static and some are dynamic?

Question

JavaScript

You need to make a script for googledoc that would send a GET request to the Ya.Metrika API, in which half of the parameters are static, the other half are dynamic and are specified as arguments to a custom function.
I tried just a string expression, into which I inserted dynamic parameters using template literals, but it didn’t even work. Although theoretically, the request should have been formed correctly. In JS, I don’t rummage from the word at all. Is there a good way?
Current non-working variant:

function GetMetrika(date1,date2,url3) {
      var metrika_api_base_url = 'https://api-metrika.yandex.ru/stat/v1/data?oauth_token=<мой токен>&ids=<id моего счётчика>&date1=${date1}&date2=${date2}&dimensions=ym%3As%3AsearchEngine&metrics=ym%3As%3Ausers&filters=ym%3As%3AstartURLPath%3D%3D${url3}&limit=10000';
      metrika_api_base_url = metrika_api_base_url;
      Logger.log(metrika_api_base_url);
      var responseJson=UrlFetchApp.fetch(metrika_api_base_url).getContentText();
      var response = JSON.parse(responseJson);
      Logger.log (responseJson);
      return response;
    }

The returned error is an invalid argument on the line:

var responseJson=UrlFetchApp.fetch(metrika_api_base_url).getContentText();

Answer 1

A good way to work with URL parameters is URLSearchParams, which automatically encodes invalid URL characters and glues all parameters into one string:

var params = new URLSearchParams();
params.append('token', 'a b c');
params.append('limit', 100);

var baseApiUrl = 'https://api-metrika.yandex.ru/stat/v1/data';
console.log(baseApiUrl + '?' + params.toString());
// → https://api-metrika.yandex.ru/stat/v1/data?token=a+b+c&limit=100