fix(react-router-dom): fix getSearchParamsForLocation in Firefox

.changeset/firefox-addons-and-web-extensions-bug.md

@@ -0,0 +1,5 @@
+---
+"react-router-dom": patch
+---
+
+Fixes an edge-case affecting web extensions in Firefox that use `URLSearchParams` and the `useSearchParams` hook.

contributors.yml

@@ -219,3 +219,4 @@
 - yuleicul
 - zheng-chuang
 - holynewbie
+- smithki

packages/react-router-dom/dom.ts

@@ -97,13 +97,18 @@ export function getSearchParamsForLocation(
  let searchParams = createSearchParams(locationSearch);
 
  if (defaultSearchParams) {
- for (let key of defaultSearchParams.keys()) {
+ // Use `defaultSearchParams.forEach(...)` here instead of iterating of
+ // `defaultSearchParams.keys()` to work-around a bug in Firefox related to
+ // web extensions. Relevant Bugzilla tickets:
+ // https://bugzilla.mozilla.org/show_bug.cgi?id=1414602
+ // https://bugzilla.mozilla.org/show_bug.cgi?id=1023984
+ defaultSearchParams.forEach((_, key) => {
  if (!searchParams.has(key)) {
  defaultSearchParams.getAll(key).forEach((value) => {
  searchParams.append(key, value);
  });
  }
- }
+ });
  }
 
  return searchParams;