diff --git a/app/ui.js b/app/ui.js
index 6ed89d68..24d32d55 100644
--- a/app/ui.js
+++ b/app/ui.js
@@ -138,10 +138,8 @@ const UI = {
 
         let autoconnect = UI.getSetting('autoconnect');
         if (autoconnect === 'true' || autoconnect == '1') {
-            autoconnect = true;
             UI.connect();
         } else {
-            autoconnect = false;
             // Show the connect panel on first load unless autoconnecting
             UI.openConnectPanel();
         }
@@ -1213,7 +1211,7 @@ const UI = {
     },
 
     securityFailed(e) {
-        let msg = "";
+        let msg;
         // On security failures we might get a string with a reason
         // directly from the server. Note that we can't control if
         // this string is translated or not.
diff --git a/core/crypto/des.js b/core/crypto/des.js
index 8dab31fb..34ee7a60 100644
--- a/core/crypto/des.js
+++ b/core/crypto/des.js
@@ -181,11 +181,11 @@ class DES {
     // Encrypt 8 bytes of text
     enc8(text) {
         const b = text.slice();
-        let i = 0, l, r, x; // left, right, accumulator
+        let l, r, x; // left, right, accumulator
 
         // Squash 8 bytes to 2 ints
-        l = b[i++]<<24 | b[i++]<<16 | b[i++]<<8 | b[i++];
-        r = b[i++]<<24 | b[i++]<<16 | b[i++]<<8 | b[i++];
+        l = b[0]<<24 | b[1]<<16 | b[2]<<8 | b[3];
+        r = b[4]<<24 | b[5]<<16 | b[6]<<8 | b[7];
 
         x = ((l >>> 4) ^ r) & 0x0f0f0f0f;
         r ^= x;
@@ -252,7 +252,7 @@ class DES {
 
         // Spread ints to bytes
         x = [r, l];
-        for (i = 0; i < 8; i++) {
+        for (let i = 0; i < 8; i++) {
             b[i] = (x[i>>>2] >>> (8 * (3 - (i % 4)))) % 256;
             if (b[i] < 0) { b[i] += 256; } // unsigned
         }
diff --git a/core/decoders/zrle.js b/core/decoders/zrle.js
index ef1726f6..b1df317a 100644
--- a/core/decoders/zrle.js
+++ b/core/decoders/zrle.js
@@ -175,7 +175,7 @@ export default class ZRLEDecoder {
 
     _readRLELength() {
         let length = 0;
-        let current = 0;
+        let current;
         do {
             current = this._inflator.inflate(1)[0];
             length += current;
diff --git a/core/rfb.js b/core/rfb.js
index 1073a878..8994317b 100644
--- a/core/rfb.js
+++ b/core/rfb.js
@@ -2949,7 +2949,7 @@ export default class RFB extends EventTargetMixin {
 
         // We need to handle errors when we requested the resize.
         if (this._FBU.x === 1 && this._FBU.y !== 0) {
-            let msg = "";
+            let msg;
             // The y-position indicates the status code from the server
             switch (this._FBU.y) {
                 case 1: