text: 'use strict';
  
  var utils = require('./../utils');
  
  function encode(val) {
    return encodeURIComponent(val).
      replace(/%40/gi, '@').
      replace(/%3A/gi, ':').
      replace(/%24/g, '$').
      replace(/%2C/gi, ',').
      replace(/%20/g, '+').
      replace(/%5B/gi, '[').
      replace(/%5D/gi, ']');
  }
  
  /**
   * Build a URL by appending params to the end
   *
   * @param {string} url The base of the url (e.g., http://www.google.com)
   * @param {object} [params] The params to be appended
   * @returns {string} The formatted url
   */
  module.exports = function buildURL(url, params, paramsSerializer) {
    /*eslint no-param-reassign:0*/
    if (!params) {
      return url;
    }
  
    var serializedParams;
    if (paramsSerializer) {
      serializedParams = paramsSerializer(params);
    } else if (utils.isURLSearchParams(params)) {
      serializedParams = params.toString();
    } else {
      var parts = [];
  
      utils.forEach(params, function serialize(val, key) {
        if (val === null || typeof val === 'undefined') {
          return;
        }
  
        if (utils.isArray(val)) {
          key = key + '[]';
        } else {
          val = [val];
        }
  
        utils.forEach(val, function parseValue(v) {
          if (utils.isDate(v)) {
            v = v.toISOString();
          } else if (utils.isObject(v)) {
            v = JSON.stringify(v);
          }
          parts.push(encode(key) + '=' + encode(v));
        });
      });
  
      serializedParams = parts.join('&');
    }
  
    if (serializedParams) {
      url += (url.indexOf('?') === -1 ? '?' : '&') + serializedParams;
    }
  
    return url;
  };
  