Explicitly define host in the url

app/frontend/controllers/search_controller.js

@@ -15,13 +15,14 @@ export default class extends Controller {
 
     const matches = /^(\w+)\[(\w+)\]$/.exec(selectEl.name)
     const rawFieldName = matches ? `${matches[1]}[${matches[2]}_raw]` : ''
+    const relativeUrlRoute = JSON.parse(this.element.dataset.info).relative_url_route
 
     accessibleAutocomplete.enhanceSelectElement({
       defaultValue: '',
       selectElement: selectEl,
       minLength: 1,
       source: (query, populateResults) => {
-        fetchAndPopulateSearchResults(query, populateResults, populateHint)
+        fetchAndPopulateSearchResults(query, populateResults, populateHint, relativeUrlRoute)
       },
       autoselect: true,
       placeholder: 'Start typing to search',

app/frontend/modules/search.js

@@ -143,17 +143,17 @@ export const enhanceOption = (option) => {
   }
 }
 
-export const fetchAndPopulateSearchResults = async (query, populateResults, populateHint) => {
+export const fetchAndPopulateSearchResults = async (query, populateResults, populateHint, relativeUrlRoute) => {
   if (/\S/.test(query)) {
-    const results = await fetchUserOptions(query)
+    const results = await fetchUserOptions(query, relativeUrlRoute)
     populateResults(Object.keys(results))
     populateHint(results)
   }
 }
 
-export const fetchUserOptions = async (query) => {
+export const fetchUserOptions = async (query, relativeUrlRoute) => {
   try {
-    const response = await fetch(`/users/search?query=${encodeURIComponent(query)}`)
+    const response = await fetch(`${relativeUrlRoute}/users/search?query=${encodeURIComponent(query)}`)
     const results = await response.json()
     return results
   } catch (error) {

app/views/filters/_select_filter.html.erb

@@ -1,6 +1,7 @@
 <%= f.govuk_select(category.to_sym,
   label: { text: label, hidden: secondary },
-  "data-controller": "search conditional-filter") do %>
+  "data-controller": "search conditional-filter",
+  "data-info": {relative_url_route: ENV["RAILS_RELATIVE_URL_ROOT"]}.to_json) do %>
     <% collection.each do |answer| %>
       <option value="<%= answer.id %>"
         data-hint="<%= answer.hint %>"