diff --git a/package.json b/package.json
index 0b1f8cc7..49ccc387 100644
--- a/package.json
+++ b/package.json
@@ -77,7 +77,7 @@
   "scripts": {
     "start": "node demo/app",
     "start-zmodem": "node demo/zmodem/app",
-    "lint": "tslint src/*.ts src/**/*.ts",
+    "lint": "tslint src/*.ts src/**/*.ts src/addons/**/*.ts",
     "test": "npm-run-all mocha lint",
     "mocha": "gulp test",
     "build:docs": "jsdoc -c jsdoc.json",
diff --git a/src/addons/attach/attach.ts b/src/addons/attach/attach.ts
index b3b2e993..4a9668de 100644
--- a/src/addons/attach/attach.ts
+++ b/src/addons/attach/attach.ts
@@ -43,7 +43,7 @@ export function attach(term: Terminal, socket: WebSocket, bidirectional: boolean
   addonTerminal.__getMessage = function(ev: MessageEvent): void {
     let str;
 
-    if (typeof ev.data == 'object') {
+    if (typeof ev.data === 'object') {
       if (!myTextDecoder) {
         myTextDecoder = new TextDecoder();
       }
@@ -53,14 +53,14 @@ export function attach(term: Terminal, socket: WebSocket, bidirectional: boolean
       } else {
         let fileReader = new FileReader();
 
-        fileReader.addEventListener('load', function() {
+        fileReader.addEventListener('load', () => {
           str = myTextDecoder.decode(this.result);
           displayData(str);
         });
         fileReader.readAsArrayBuffer(ev.data);
       }
-    } else if (typeof ev.data == 'string') {
-      displayData(ev.data)
+    } else if (typeof ev.data === 'string') {
+      displayData(ev.data);
     } else {
       throw Error(`Cannot handle "${typeof ev.data}" websocket message.`);
     }
@@ -73,7 +73,7 @@ export function attach(term: Terminal, socket: WebSocket, bidirectional: boolean
   * @param str String decoded by FileReader.
   * @param data The data of the EventMessage.
   */
-  function displayData(str?: string, data?: string) {
+  function displayData(str?: string, data?: string): void {
     if (buffered) {
       addonTerminal.__pushToBuffer(str || data);
     } else {
diff --git a/src/addons/zmodem/zmodem.ts b/src/addons/zmodem/zmodem.ts
index 297ebe34..4f2f4a91 100644
--- a/src/addons/zmodem/zmodem.ts
+++ b/src/addons/zmodem/zmodem.ts
@@ -43,8 +43,7 @@ export interface IZmodemOptions {
 }
 
 function zmodemAttach(ws: WebSocket, opts: IZmodemOptions = {}): void {
-  var term = this;
-
+  const term = this;
   const senderFunc = (octets: ArrayLike<number>) => ws.send(new Uint8Array(octets));
 
   let zsentry;