diff --git a/demo/client.ts b/demo/client.ts
index 08545c09d..4af03548b 100644
--- a/demo/client.ts
+++ b/demo/client.ts
@@ -100,7 +100,7 @@ function createTerminal(): void {
   addDomListener(actionElements.findNext, 'keypress', (e) => {
     if (e.key === 'Enter') {
       e.preventDefault();
-      let searchOptions = {
+      const searchOptions = {
         regex: (document.getElementById('regex') as HTMLInputElement).checked,
         wholeWord: false,
         caseSensitive: false
@@ -111,7 +111,7 @@ function createTerminal(): void {
   addDomListener(actionElements.findPrevious, 'keypress', (e) => {
     if (e.key === 'Enter') {
       e.preventDefault();
-      let searchOptions = {
+      const searchOptions = {
         regex: (document.getElementById('regex') as HTMLInputElement).checked,
         wholeWord: false,
         caseSensitive: false
diff --git a/package.json b/package.json
index f2591d038..468c027ed 100644
--- a/package.json
+++ b/package.json
@@ -50,7 +50,7 @@
   "scripts": {
     "start": "node demo/start",
     "start-zmodem": "node demo/zmodem/app",
-    "lint": "tslint 'src/**/*.ts'",
+    "lint": "tslint 'src/**/*.ts' './demo/**/*.ts'",
     "test": "npm-run-all mocha lint",
     "test-debug": "node --inspect-brk node_modules/.bin/gulp test",
     "test-suite": "gulp mocha-suite --test",
diff --git a/src/Linkifier.ts b/src/Linkifier.ts
index 44a91a36e..17e59f1cb 100644
--- a/src/Linkifier.ts
+++ b/src/Linkifier.ts
@@ -191,8 +191,11 @@ export class Linkifier extends EventEmitter implements ILinkifier {
       const bufferIndex = this._terminal.buffer.stringIndexToBufferIndex(rowIndex, stringIndex);
       const line = this._terminal.buffer.lines.get(bufferIndex[0]);
       const char = line.get(bufferIndex[1]);
-      const attr: number = char[CHAR_DATA_ATTR_INDEX];
-      const fg = (attr >> 9) & 0x1ff;
+      let fg: number | undefined;
+      if (char) {
+        const attr: number = char[CHAR_DATA_ATTR_INDEX];
+        fg = (attr >> 9) & 0x1ff;
+      }
 
       if (matcher.validationCallback) {
         matcher.validationCallback(uri, isValid => {