create working extension with eslint configured locally

eslint-example/file.js

@@ -1,12 +1,4 @@
-function getJSON(url, callback) {
-    let xhr = new XMLHttpRequest();
-    xhr.onload = function() {
-        callback(this.responseText);
-    };
-    xhr.open("GET", url, true);
-    xhr.send();
-}
-
-export function getUsefulContents(url, callback) {
-    getJSON(url, data => callback(JSON.parse(data)));
+// we cant use export here
+function getUsefulContents(callback) {
+    callback('Hello World');
 }