Use fetch

app/javascript/controllers/soft_validations_controller.js

@@ -5,13 +5,10 @@ export default class extends Controller {
 
   initialize() {
     let url = window.location.href + "/soft_validations"
-    let xhr = new XMLHttpRequest()
     let div = this.overrideTarget
-    xhr.open("GET", url, true)
-    xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded")
-    xhr.onreadystatechange = function () {
-            if (this.readyState == 4 && this.status == 200) {
-              let response = JSON.parse(this.response)
+    fetch(url, { headers: { accept: "application/json" } })
+      .then(response => response.json())
+      .then((response) => {
         if(response["show"]){
           div.style.display = "block"
           let innerHTML = div.innerHTML
@@ -22,11 +19,10 @@ export default class extends Controller {
           div.style.display = "none"
           let buttons = document.getElementsByName(`case_log[override_net_income_validation][]`)
           Object.entries(buttons).forEach(([idx, button]) => {
-                    button.checked = false;
+            button.checked = false
           })
         }
       }
-        }
-    xhr.send()
+    )
   }
 }