SCRIPT5009: 'URLSearchParams' is undefined in IE 11

Got a solution by replacing the code with the following:

$.urlParam = function(name){
    var results = new RegExp('[\?&]' + name + '=([^&#]*)').exec(window.location.href);
    if (results == null){
       return null;
    }
    else {
       return decodeURI(results[1]) || 0;
    }
}

So for example "example.com?param1=name&param2=&id=6"

$.urlParam('param1');  // name
$.urlParam('id');      // 6
$.urlParam('param2');  // null

Odhikari's answer as a (partial) polyfill:

(function (w) {

    w.URLSearchParams = w.URLSearchParams || function (searchString) {
        var self = this;
        self.searchString = searchString;
        self.get = function (name) {
            var results = new RegExp('[\?&]' + name + '=([^&#]*)').exec(self.searchString);
            if (results == null) {
                return null;
            }
            else {
                return decodeURI(results[1]) || 0;
            }
        };
    }

})(window)

If anyone finds this in 2019, corejs now also supports URLSearchParams as a polyfill, so you can just stay with corejs and don't have to brew together something yourselves.

import 'core-js/features/url-search-params';

https://github.com/zloirock/core-js#url-and-urlsearchparams

I was able to solve this by using url-search-params-polyfill. Just import into the file you're using URLSearchParams in:

import 'url-search-params-polyfill';

And your existing references to URLSearchParams should now work!

I have had a similar issue when trying to use URLSearchParams when trying to make an AXIOS Post when using Internet Explorer. So its a little different from your description, but I'd like to post my resolution here just in case.

Here's my AXIOS post code from my React app that works just fine for Edge, Chrome and Firefox, but on IE it gives me the error

SCRIPT5009: URLSearchParams is undefined

:

        let axiosConfig = {
            headers: {
                'Content-Type': 'application/x-www-form-urlencoded'
            }
        };            
        // Putting together the data to be passed to local servlet.
        const params = new URLSearchParams();
        params.append('var1', this.state.data1);
        params.append('var2', this.state.data2);

        var urlToPost = 'https://localhost:8080/someLocalServlet/doSomething';

        var self = this;  
        axios.post(urlToPost, params, axiosConfig)
            .then((res) => {
                // Handling Response from Servlet.
                console.log("AXIOS POST RESPONSE RECEIVED: ", res);

            })
            .catch((err) => {
                // Handler exception error thrown by Servlet.
                console.log("AXIOS POST ERROR: ", err);

            })     

To get it to work with IE I used jQuery to do the Post and used a var object instead of URLSearchParams. The if statement below checks to see if the user is on IE :

    if((navigator.userAgent.indexOf("MSIE") !== -1 ) || (!!document.documentMode === true )) { //IF IE > 10
        var myObject = {
            var1: this.state.data1,
            var2: this.state.data2
        };
        var urlToPostTo = 'https://localhost:8080/someLocalServlet/doSomething';

        $.post(urlToPost, myObject, 
            function(result) {  
                alert( "success" );
            })
              .done(function(result) {
                alert( "second success" );
              })
              .fail(function(result) {
                alert( "error" );
              })
              .always(function(result) {
                    alert( "finished" );
              });        
    } else {
       // use the AXIOS POST code above
    }

To get the jQuery, I did have to do

npm install jquery

Then on top of my React file I imported the following:

import $ from 'jquery'; 
import { polyfill } from 'es6-promise'; polyfill();