Migrate javascript action (#21)

get-latest-version.js

@@ -0,0 +1,25 @@
+const XMLHttpRequest = require("xmlhttprequest").XMLHttpRequest;
+
+function getLatestVersion() {
+  // return new Promise((resolve, reject) => {
+  return new Promise(resolve => {
+    const xhr = new XMLHttpRequest();
+    const url = "https://api.github.com/repos/gohugoio/hugo/releases/latest";
+    xhr.open("GET", url);
+    xhr.send();
+
+    xhr.onreadystatechange = function() {
+      if (xhr.readyState === 4 && xhr.status === 200) {
+        const result = JSON.parse(xhr.responseText);
+        const latestURL = result["assets"][0].browser_download_url;
+        const latestVersion = latestURL.match(/(\d+).(\d+).(\d+)/g)[0];
+
+        resolve(latestVersion);
+        // } else {
+        //   reject(`ERROR: got status ${xhr.status}`);
+      }
+    };
+  });
+}
+
+module.exports = getLatestVersion;