diff --git a/demo/start.js b/demo/start.js
index 78f1ff1d..278c572f 100644
--- a/demo/start.js
+++ b/demo/start.js
@@ -5,7 +5,6 @@
  * This file is the entry point for browserify.
  */
 
-const cp = require('child_process');
 const path = require('path');
 const webpack = require('webpack');
 const startServer = require('./server.js');
diff --git a/src/Buffer.test.ts b/src/Buffer.test.ts
index 1ef2e92c..a56fd63a 100644
--- a/src/Buffer.test.ts
+++ b/src/Buffer.test.ts
@@ -19,8 +19,8 @@ describe('Buffer', () => {
 
   beforeEach(() => {
     terminal = new MockTerminal();
-    terminal.cols = INIT_COLS;
-    terminal.rows = INIT_ROWS;
+    (terminal as any).cols = INIT_COLS;
+    (terminal as any).rows = INIT_ROWS;
     terminal.options.scrollback = 1000;
     buffer = new Buffer(terminal, true);
   });
diff --git a/src/BufferSet.test.ts b/src/BufferSet.test.ts
index 26f9cd42..576a8ca4 100644
--- a/src/BufferSet.test.ts
+++ b/src/BufferSet.test.ts
@@ -15,8 +15,8 @@ describe('BufferSet', () => {
 
   beforeEach(() => {
     terminal = new MockTerminal();
-    terminal.cols = 80;
-    terminal.rows = 24;
+    (terminal as any).cols = 80;
+    (terminal as any).rows = 24;
     terminal.options.scrollback = 1000;
     bufferSet = new BufferSet(terminal);
   });
diff --git a/src/Linkifier.test.ts b/src/Linkifier.test.ts
index 0ba1294a..07dbf1b3 100644
--- a/src/Linkifier.test.ts
+++ b/src/Linkifier.test.ts
@@ -41,8 +41,8 @@ describe('Linkifier', () => {
 
   beforeEach(() => {
     terminal = new MockTerminal();
-    terminal.cols = 100;
-    terminal.rows = 10;
+    (terminal as any).cols = 100;
+    (terminal as any).rows = 10;
     terminal.buffer = new MockBuffer();
     (<MockBuffer>terminal.buffer).setLines(new CircularList<IBufferLine>(20));
     terminal.buffer.ydisp = 0;
@@ -65,7 +65,7 @@ describe('Linkifier', () => {
   function assertLinkifiesRow(rowText: string, linkMatcherRegex: RegExp, links: {x: number, length: number}[], done: MochaDone): void {
     addRow(rowText);
     linkifier.registerLinkMatcher(linkMatcherRegex, () => {});
-    terminal.rows = terminal.buffer.lines.length - 1;
+    (terminal as any).rows = terminal.buffer.lines.length - 1;
     linkifier.linkifyRows();
     // Allow linkify to happen
     setTimeout(() => {
@@ -142,19 +142,19 @@ describe('Linkifier', () => {
       });
       describe('multi-line links', () => {
         it('should match links that start on line 1/2 of a wrapped line and end on the last character of line 1/2', done => {
-          terminal.cols = 4;
+          (terminal as any).cols = 4;
           assertLinkifiesMultiLineLink('12345', /1234/, [{x1: 0, x2: 4, y1: 0, y2: 0}], done);
         });
         it('should match links that start on line 1/2 of a wrapped line and wrap to line 2/2', done => {
-          terminal.cols = 4;
+          (terminal as any).cols = 4;
           assertLinkifiesMultiLineLink('12345', /12345/, [{x1: 0, x2: 1, y1: 0, y2: 1}], done);
         });
         it('should match links that start and end on line 2/2 of a wrapped line', done => {
-          terminal.cols = 4;
+          (terminal as any).cols = 4;
           assertLinkifiesMultiLineLink('12345678', /5678/, [{x1: 0, x2: 4, y1: 1, y2: 1}], done);
         });
         it('should match links that start on line 2/3 of a wrapped line and wrap to line 3/3', done => {
-          terminal.cols = 4;
+          (terminal as any).cols = 4;
           assertLinkifiesMultiLineLink('123456789', /56789/, [{x1: 0, x2: 1, y1: 1, y2: 2}], done);
         });
       });
diff --git a/src/SelectionManager.test.ts b/src/SelectionManager.test.ts
index 2f74ccda..21bc6754 100644
--- a/src/SelectionManager.test.ts
+++ b/src/SelectionManager.test.ts
@@ -45,8 +45,8 @@ describe('SelectionManager', () => {
 
   beforeEach(() => {
     terminal = new TestMockTerminal();
-    terminal.cols = 80;
-    terminal.rows = 2;
+    (terminal as any).cols = 80;
+    (terminal as any).rows = 2;
     terminal.options.scrollback = 100;
     terminal.buffers = new BufferSet(terminal);
     terminal.buffer = terminal.buffers.active;
diff --git a/src/SelectionModel.test.ts b/src/SelectionModel.test.ts
index 8d4b30bb..d49f41d0 100644
--- a/src/SelectionModel.test.ts
+++ b/src/SelectionModel.test.ts
@@ -23,8 +23,8 @@ describe('SelectionManager', () => {
 
   beforeEach(() => {
     terminal = new MockTerminal();
-    terminal.cols = 80;
-    terminal.rows = 2;
+    (terminal as any).cols = 80;
+    (terminal as any).rows = 2;
     terminal.options.scrollback = 10;
     terminal.buffers = new BufferSet(terminal);
     terminal.buffer = terminal.buffers.active;
diff --git a/src/Types.ts b/src/Types.ts
index aac029f2..31e42339 100644
--- a/src/Types.ts
+++ b/src/Types.ts
@@ -237,7 +237,7 @@ export interface IBufferAccessor {
 }
 
 export interface IElementAccessor {
-  element: HTMLElement;
+  readonly element: HTMLElement;
 }
 
 export interface ILinkifierAccessor {
diff --git a/src/common/CircularList.ts b/src/common/CircularList.ts
index af4d8af5..90891b72 100644
--- a/src/common/CircularList.ts
+++ b/src/common/CircularList.ts
@@ -154,24 +154,22 @@ export class CircularList<T> extends EventEmitter implements ICircularList<T> {
       this._length -= deleteCount;
     }
 
-    if (items && items.length) {
-      // Add items
-      for (let i = this._length - 1; i >= start; i--) {
-        this._array[this._getCyclicIndex(i + items.length)] = this._array[this._getCyclicIndex(i)];
-      }
-      for (let i = 0; i < items.length; i++) {
-        this._array[this._getCyclicIndex(start + i)] = items[i];
-      }
+    // Add items
+    for (let i = this._length - 1; i >= start; i--) {
+      this._array[this._getCyclicIndex(i + items.length)] = this._array[this._getCyclicIndex(i)];
+    }
+    for (let i = 0; i < items.length; i++) {
+      this._array[this._getCyclicIndex(start + i)] = items[i];
+    }
 
-      // Adjust length as needed
-      if (this._length + items.length > this._maxLength) {
-        const countToTrim = (this._length + items.length) - this._maxLength;
-        this._startIndex += countToTrim;
-        this._length = this._maxLength;
-        this.emitMayRemoveListeners('trim', countToTrim);
-      } else {
-        this._length += items.length;
-      }
+    // Adjust length as needed
+    if (this._length + items.length > this._maxLength) {
+      const countToTrim = (this._length + items.length) - this._maxLength;
+      this._startIndex += countToTrim;
+      this._length = this._maxLength;
+      this.emitMayRemoveListeners('trim', countToTrim);
+    } else {
+      this._length += items.length;
     }
   }
 
diff --git a/typings/xterm.d.ts b/typings/xterm.d.ts
index 11fab909..dc9ebbae 100644
--- a/typings/xterm.d.ts
+++ b/typings/xterm.d.ts
@@ -314,28 +314,32 @@ declare module 'xterm' {
     /**
      * The element containing the terminal.
      */
-    element: HTMLElement;
+    readonly element: HTMLElement;
 
     /**
      * The textarea that accepts input for the terminal.
      */
-    textarea: HTMLTextAreaElement;
+    readonly textarea: HTMLTextAreaElement;
 
     /**
-     * The number of rows in the terminal's viewport.
+     * The number of rows in the terminal's viewport. Use
+     * `ITerminalOptions.rows` to set this in the constructor and
+     * `Terminal.resize` for when the terminal exists.
      */
-    rows: number;
+    readonly rows: number;
 
     /**
-     * The number of columns in the terminal's viewport.
+     * The number of columns in the terminal's viewport. Use
+     * `ITerminalOptions.cols` to set this in the constructor and
+     * `Terminal.resize` for when the terminal exists.
      */
-    cols: number;
+    readonly cols: number;
 
     /**
      * (EXPERIMENTAL) Get all markers registered against the buffer. If the alt
      * buffer is active this will always return [].
      */
-    markers: IMarker[];
+    readonly markers: IMarker[];
 
     /**
      * Natural language strings that can be localized.