replaced code double up

src/background.js

@@ -163,56 +163,40 @@ function download(url, fileName, cb) {
     let file = fs.createWriteStream(dest);
     var partiallength = 0 //sets partiallength to 0
 
-    if(new URL(url).protocol == "https:") {
-      let request = https.get(url, function(response) {
-          response.pipe(file);
-
-          var totallength = parseInt(response.headers['content-length'], 10); //sets totallength of file
-          response.on("data", function(chunk) {
-            partiallength += chunk.length //adds each time
-            let decimallength = partiallength / totallength
-            if (decimallength != 1) {
-              win.setProgressBar(decimallength) //sets progress bar to decimal
-              win.webContents.send("downloadProgress", decimallength)
-            }
-            else {
-              win.setProgressBar(0) //sets progress bar to blank when done
-              win.webContents.send("downloadProgress", 0)
-            }
-          });
-
-          file.on('finish', function() {
-              file.close(cb(null, dest)); // async call of the callback
-          });
-      }).on('error', function(err) { // Handle errors
-          fs.unlink(dest); // Delete the file async. (But we don't check the result)
-          if (cb) cb(err.message, dest);
-      });
-
-    } else {
-      let request = http.get(url, function(response) {
-          response.pipe(file);
-
-          var totallength = parseInt(response.headers['content-length'], 10); //sets totallength of file
-          response.on("data", function(chunk) {
-            partiallength += chunk.length //adds each time
-            let decimallength = partiallength / totallength
-            if (decimallength != 1) {
-              win.setProgressBar(decimallength) //sets progress bar to decimal
-              win.webContents.send("downloadProgress", decimallength)
-            }
-            else {
-              win.setProgressBar(0) //sets progress bar to blank when done
-              win.webContents.send("downloadProgress", 0)
-            }
-          });
-          
-          file.on('finish', function() {
-              file.close(cb(null, dest)); // async call of the callback
-          });
-      }).on('error', function(err) { // Handle errors
-          fs.unlink(dest); // Delete the file async. (But we don't check the result)
-          if (cb) cb(err.message, dest);
-      });
-    }
+    //Replaced code double up: https://stackoverflow.com/a/38465918
+    var protocol = (function() { 
+      var url = require('url'),
+        adapters = {
+          'http:': http,
+          'https:': https,
+        };
+      return function(inputUrl) {
+        return adapters[url.parse(inputUrl).protocol]
+      }
+    }());
+
+    let request = protocol(url).get(url, function(response) {
+        response.pipe(file);
+
+        var totallength = parseInt(response.headers['content-length'], 10); //sets totallength of file
+        response.on("data", function(chunk) {
+          partiallength += chunk.length //adds each time
+          let decimallength = partiallength / totallength
+          if (decimallength != 1) {
+            win.setProgressBar(decimallength) //sets progress bar to decimal
+            win.webContents.send("downloadProgress", decimallength)
+          }
+          else {
+            win.setProgressBar(0) //sets progress bar to blank when done
+            win.webContents.send("downloadProgress", 0)
+          }
+        });
+
+        file.on('finish', function() {
+            file.close(cb(null, dest)); // async call of the callback
+        });
+    }).on('error', function(err) { // Handle errors
+        fs.unlink(dest); // Delete the file async. (But we don't check the result)
+        if (cb) cb(err.message, dest);
+    });
 };
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