diff --git a/addons/xterm-addon-webgl/src/GlyphRenderer.ts b/addons/xterm-addon-webgl/src/GlyphRenderer.ts
index 186cb2c1b8..bd4488dc1a 100644
--- a/addons/xterm-addon-webgl/src/GlyphRenderer.ts
+++ b/addons/xterm-addon-webgl/src/GlyphRenderer.ts
@@ -105,9 +105,6 @@ export class GlyphRenderer {
     const gl = this._gl;
 
     const program = throwIfFalsy(createProgram(gl, vertexShaderSource, fragmentShaderSource));
-    if (program === undefined) {
-      throw new Error('Could not create WebGL program');
-    }
     this._program = program;
 
     // Uniform locations
diff --git a/addons/xterm-addon-webgl/src/WebglRenderer.ts b/addons/xterm-addon-webgl/src/WebglRenderer.ts
index 3d41e1b55c..3f8163ba0a 100644
--- a/addons/xterm-addon-webgl/src/WebglRenderer.ts
+++ b/addons/xterm-addon-webgl/src/WebglRenderer.ts
@@ -14,7 +14,7 @@ import { IWebGL2RenderingContext } from './Types';
 import { INVERTED_DEFAULT_COLOR } from 'browser/renderer/atlas/Constants';
 import { RenderModel, COMBINED_CHAR_BIT_MASK } from './RenderModel';
 import { Disposable } from 'common/Lifecycle';
-import { DEFAULT_COLOR, CHAR_DATA_CHAR_INDEX, CHAR_DATA_CODE_INDEX, CHAR_DATA_ATTR_INDEX, NULL_CELL_CODE } from 'common/buffer/Constants';
+import { DEFAULT_COLOR, CHAR_DATA_CHAR_INDEX, CHAR_DATA_CODE_INDEX, NULL_CELL_CODE } from 'common/buffer/Constants';
 import { Terminal } from 'xterm';
 import { getLuminance } from './ColorUtils';
 import { IRenderLayer } from './renderLayer/Types';
diff --git a/demo/server.js b/demo/server.js
index 9a45d06fc5..f04705aa9e 100644
--- a/demo/server.js
+++ b/demo/server.js
@@ -14,24 +14,26 @@ function startServer() {
       logs = {};
 
   app.use('/xterm.css', express.static(__dirname + '/../css/xterm.css'));
-  app.get('/logo.png', (req, res) => res.sendFile(__dirname + '/logo.png'));
+  app.get('/logo.png', (req, res) => {
+    res.sendFile(__dirname + '/logo.png'); // lgtm [js/missing-rate-limiting]
+  });
 
-  app.get('/', function(req, res){
-    res.sendFile(__dirname + '/index.html');
+  app.get('/', (req, res) => {
+    res.sendFile(__dirname + '/index.html'); // lgtm [js/missing-rate-limiting]
   });
 
-  app.get('/test', function(req, res){
-    res.sendFile(__dirname + '/test.html');
+  app.get('/test', (req, res) => {
+    res.sendFile(__dirname + '/test.html'); // lgtm [js/missing-rate-limiting]
   });
 
-  app.get('/style.css', function(req, res){
-    res.sendFile(__dirname + '/style.css');
+  app.get('/style.css', (req, res) => {
+    res.sendFile(__dirname + '/style.css'); // lgtm [js/missing-rate-limiting]
   });
 
   app.use('/dist', express.static(__dirname + '/dist'));
   app.use('/src', express.static(__dirname + '/src'));
 
-  app.post('/terminals', function (req, res) {
+  app.post('/terminals', (req, res) => {
     const env = Object.assign({}, process.env);
     env['COLORTERM'] = 'truecolor';
     var cols = parseInt(req.query.cols),
@@ -55,7 +57,7 @@ function startServer() {
     res.end();
   });
 
-  app.post('/terminals/:pid/size', function (req, res) {
+  app.post('/terminals/:pid/size', (req, res) => {
     var pid = parseInt(req.params.pid),
         cols = parseInt(req.query.cols),
         rows = parseInt(req.query.rows),
diff --git a/src/Terminal.ts b/src/Terminal.ts
index 852d424d28..597c14cd8d 100644
--- a/src/Terminal.ts
+++ b/src/Terminal.ts
@@ -383,18 +383,6 @@ export class Terminal extends Disposable implements ITerminal, IDisposable, IInp
         case 'theme':
           this._setTheme(this.optionsService.options.theme);
           break;
-        case 'scrollback':
-          const newBufferLength = this.rows + this.optionsService.options.scrollback;
-          if (this.buffer.lines.length > newBufferLength) {
-            const amountToTrim = this.buffer.lines.length - newBufferLength;
-            const needsRefresh = (this.buffer.ydisp - amountToTrim < 0);
-            this.buffer.lines.trimStart(amountToTrim);
-            this.buffer.ybase = Math.max(this.buffer.ybase - amountToTrim, 0);
-            this.buffer.ydisp = Math.max(this.buffer.ydisp - amountToTrim, 0);
-            if (needsRefresh) {
-              this.refresh(0, this.rows - 1);
-            }
-          }
         case 'windowsMode':
           if (this.optionsService.options.windowsMode) {
             if (!this._windowsMode) {
diff --git a/src/browser/renderer/CharacterJoinerRegistry.ts b/src/browser/renderer/CharacterJoinerRegistry.ts
index a5abe80f56..5385b76b42 100644
--- a/src/browser/renderer/CharacterJoinerRegistry.ts
+++ b/src/browser/renderer/CharacterJoinerRegistry.ts
@@ -303,7 +303,6 @@ export class CharacterJoinerRegistry implements ICharacterJoinerRegistry {
           // current range
           ranges[i - 1][1] = Math.max(newRange[1], range[1]);
           ranges.splice(i, 1);
-          inRange = false;
           return ranges;
         }
 
diff --git a/src/browser/renderer/dom/DomRendererRowFactory.ts b/src/browser/renderer/dom/DomRendererRowFactory.ts
index 316645f829..3e3b5df0d3 100644
--- a/src/browser/renderer/dom/DomRendererRowFactory.ts
+++ b/src/browser/renderer/dom/DomRendererRowFactory.ts
@@ -8,7 +8,7 @@ import { INVERTED_DEFAULT_COLOR } from 'browser/renderer/atlas/Constants';
 import { AttributeData } from 'common/buffer/AttributeData';
 import { NULL_CELL_CODE, WHITESPACE_CELL_CHAR } from 'common/buffer/Constants';
 import { CellData } from 'common/buffer/CellData';
-import { ITerminalOptions, IOptionsService } from 'common/services/Services';
+import { IOptionsService } from 'common/services/Services';
 
 export const BOLD_CLASS = 'xterm-bold';
 export const DIM_CLASS = 'xterm-dim';
diff --git a/src/common/buffer/BufferLine.ts b/src/common/buffer/BufferLine.ts
index 8e742be38f..1e95e0045b 100644
--- a/src/common/buffer/BufferLine.ts
+++ b/src/common/buffer/BufferLine.ts
@@ -5,7 +5,7 @@
 
 import { CharData, IBufferLine, ICellData } from 'common/Types';
 import { stringFromCodePoint } from 'common/input/TextDecoder';
-import { DEFAULT_COLOR, CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX, CHAR_DATA_ATTR_INDEX, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE, WHITESPACE_CELL_CHAR, Content } from 'common/buffer/Constants';
+import { CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX, CHAR_DATA_ATTR_INDEX, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE, WHITESPACE_CELL_CHAR, Content } from 'common/buffer/Constants';
 import { CellData } from 'common/buffer/CellData';
 import { AttributeData } from 'common/buffer/AttributeData';
 
diff --git a/src/public/Terminal.ts b/src/public/Terminal.ts
index b72a4cff4b..fe34cb36fa 100644
--- a/src/public/Terminal.ts
+++ b/src/public/Terminal.ts
@@ -181,7 +181,7 @@ export class Terminal implements ITerminalApi {
 
   private _verifyIntegers(...values: number[]): void {
     values.forEach(value => {
-      if (value === Infinity || value === NaN || value % 1 !== 0) {
+      if (value === Infinity || isNaN(value) || value % 1 !== 0) {
         throw new Error('This API only accepts integers');
       }
     });