diff --git a/package.json b/package.json
index c416e4f469..f2591d0383 100644
--- a/package.json
+++ b/package.json
@@ -40,7 +40,7 @@
     "ts-loader": "^4.5.0",
     "tslint": "^5.9.1",
     "tslint-consistent-codestyle": "^1.13.0",
-    "typescript": "2.8.3",
+    "typescript": "3.0",
     "vinyl-buffer": "^1.0.0",
     "vinyl-source-stream": "^1.1.0",
     "webpack": "^4.17.1",
diff --git a/src/Buffer.ts b/src/Buffer.ts
index 81b8a517dc..9487be4a67 100644
--- a/src/Buffer.ts
+++ b/src/Buffer.ts
@@ -5,7 +5,7 @@
 
 import { CircularList } from './common/CircularList';
 import { CharData, ITerminal, IBuffer, IBufferLine } from './Types';
-import { EventEmitter } from './EventEmitter';
+import { EventEmitter } from './common/EventEmitter';
 import { IMarker } from 'xterm';
 import { BufferLine } from './BufferLine';
 
diff --git a/src/BufferSet.ts b/src/BufferSet.ts
index 4b5ca2d13b..c91ab751f1 100644
--- a/src/BufferSet.ts
+++ b/src/BufferSet.ts
@@ -5,7 +5,7 @@
 
 import { ITerminal, IBufferSet } from './Types';
 import { Buffer } from './Buffer';
-import { EventEmitter } from './EventEmitter';
+import { EventEmitter } from './common/EventEmitter';
 
 /**
  * The BufferSet represents the set of two buffers used by xterm terminals (normal and alt) and
diff --git a/src/Linkifier.ts b/src/Linkifier.ts
index 8615daf8e7..74fc72db8a 100644
--- a/src/Linkifier.ts
+++ b/src/Linkifier.ts
@@ -6,7 +6,7 @@
 import { IMouseZoneManager } from './ui/Types';
 import { ILinkHoverEvent, ILinkMatcher, LinkMatcherHandler, LinkHoverEventTypes, ILinkMatcherOptions, ILinkifier, ITerminal, IBufferLine } from './Types';
 import { MouseZone } from './ui/MouseZoneManager';
-import { EventEmitter } from './EventEmitter';
+import { EventEmitter } from './common/EventEmitter';
 import { CHAR_DATA_ATTR_INDEX } from './Buffer';
 
 /**
diff --git a/src/SelectionManager.ts b/src/SelectionManager.ts
index 2dd92c5b62..bfb5717732 100644
--- a/src/SelectionManager.ts
+++ b/src/SelectionManager.ts
@@ -3,11 +3,12 @@
  * @license MIT
  */
 
-import { ITerminal, ISelectionManager, IBuffer, CharData, XtermListener, IBufferLine } from './Types';
+import { ITerminal, ISelectionManager, IBuffer, CharData, IBufferLine } from './Types';
+import { XtermListener } from './common/Types';
 import { MouseHelper } from './utils/MouseHelper';
 import * as Browser from './shared/utils/Browser';
 import { CharMeasure } from './ui/CharMeasure';
-import { EventEmitter } from './EventEmitter';
+import { EventEmitter } from './common/EventEmitter';
 import { SelectionModel } from './SelectionModel';
 import { CHAR_DATA_WIDTH_INDEX, CHAR_DATA_CHAR_INDEX, CHAR_DATA_CODE_INDEX } from './Buffer';
 import { AltClickHandler } from './handlers/AltClickHandler';
diff --git a/src/Terminal.ts b/src/Terminal.ts
index 3927d8b5da..ef9cb9ab68 100644
--- a/src/Terminal.ts
+++ b/src/Terminal.ts
@@ -27,7 +27,7 @@ import { IRenderer } from './renderer/Types';
 import { BufferSet } from './BufferSet';
 import { Buffer, MAX_BUFFER_SIZE, DEFAULT_ATTR, NULL_CELL_CODE, NULL_CELL_WIDTH, NULL_CELL_CHAR } from './Buffer';
 import { CompositionHelper } from './CompositionHelper';
-import { EventEmitter } from './EventEmitter';
+import { EventEmitter } from './common/EventEmitter';
 import { Viewport } from './Viewport';
 import { rightClickHandler, moveTextAreaUnderMouseCursor, pasteHandler, copyHandler } from './handlers/Clipboard';
 import { C0 } from './common/data/EscapeSequences';
diff --git a/src/Types.ts b/src/Types.ts
index 21c6c57105..df3f1a7984 100644
--- a/src/Types.ts
+++ b/src/Types.ts
@@ -7,11 +7,10 @@ import { Terminal as PublicTerminal, ITerminalOptions as IPublicTerminalOptions,
 import { IColorSet, IRenderer } from './renderer/Types';
 import { IMouseZoneManager } from './ui/Types';
 import { ICharset } from './core/Types';
+import { ICircularList } from './common/Types';
 
 export type CustomKeyEventHandler = (event: KeyboardEvent) => boolean;
 
-export type XtermListener = (...args: any[]) => void;
-
 export type CharData = [number, string, number, number];
 export type LineData = CharData[];
 
@@ -294,19 +293,6 @@ export interface IBufferSet extends IEventEmitter {
   activateAltBuffer(): void;
 }
 
-export interface ICircularList<T> extends IEventEmitter {
-  length: number;
-  maxLength: number;
-
-  get(index: number): T;
-  set(index: number, value: T): void;
-  push(value: T): void;
-  pop(): T;
-  splice(start: number, deleteCount: number, ...items: T[]): void;
-  trimStart(count: number): void;
-  shiftElements(start: number, count: number, offset: number): void;
-}
-
 export interface ISelectionManager {
   selectionText: string;
   selectionStart: [number, number];
diff --git a/src/common/CircularList.ts b/src/common/CircularList.ts
index ca83d6e172..542dbf12ab 100644
--- a/src/common/CircularList.ts
+++ b/src/common/CircularList.ts
@@ -3,15 +3,15 @@
  * @license MIT
  */
 
-import { EventEmitter } from '../EventEmitter';
-import { ICircularList } from '../Types';
+import { EventEmitter } from './EventEmitter';
+import { ICircularList } from './Types';
 
 /**
  * Represents a circular list; a list with a maximum size that wraps around when push is called,
  * overriding values at the start of the list.
  */
 export class CircularList<T> extends EventEmitter implements ICircularList<T> {
-  protected _array: T[];
+  protected _array: (T | undefined)[];
   private _startIndex: number;
   private _length: number;
 
@@ -36,7 +36,7 @@ export class CircularList<T> extends EventEmitter implements ICircularList<T> {
 
     // Reconstruct array, starting at index 0. Only transfer values from the
     // indexes 0 to length.
-    const newArray = new Array<T>(newMaxLength);
+    const newArray = new Array<T | undefined>(newMaxLength);
     for (let i = 0; i < Math.min(newMaxLength, this.length); i++) {
       newArray[i] = this._array[this._getCyclicIndex(i)];
     }
@@ -66,7 +66,7 @@ export class CircularList<T> extends EventEmitter implements ICircularList<T> {
    * @param index The index of the value to get.
    * @return The value corresponding to the index.
    */
-  public get(index: number): T {
+  public get(index: number): T | undefined {
     return this._array[this._getCyclicIndex(index)];
   }
 
@@ -78,7 +78,7 @@ export class CircularList<T> extends EventEmitter implements ICircularList<T> {
    * @param index The index to set.
    * @param value The value to set.
    */
-  public set(index: number, value: T): void {
+  public set(index: number, value: T | undefined): void {
     this._array[this._getCyclicIndex(index)] = value;
   }
 
@@ -104,7 +104,7 @@ export class CircularList<T> extends EventEmitter implements ICircularList<T> {
    * Removes and returns the last value on the list.
    * @return The popped value.
    */
-  public pop(): T {
+  public pop(): T | undefined {
     return this._array[this._getCyclicIndex(this._length-- - 1)];
   }
 
diff --git a/src/EventEmitter.test.ts b/src/common/EventEmitter.test.ts
similarity index 100%
rename from src/EventEmitter.test.ts
rename to src/common/EventEmitter.test.ts
diff --git a/src/EventEmitter.ts b/src/common/EventEmitter.ts
similarity index 94%
rename from src/EventEmitter.ts
rename to src/common/EventEmitter.ts
index 0de5999ae1..ae8f0069dc 100644
--- a/src/EventEmitter.ts
+++ b/src/common/EventEmitter.ts
@@ -5,7 +5,7 @@
 
 import { XtermListener } from './Types';
 import { IEventEmitter, IDisposable } from 'xterm';
-import { Disposable } from './common/Lifecycle';
+import { Disposable } from './Lifecycle';
 
 export class EventEmitter extends Disposable implements IEventEmitter, IDisposable {
   private _events: {[type: string]: XtermListener[]};
@@ -30,14 +30,15 @@ export class EventEmitter extends Disposable implements IEventEmitter, IDisposab
   public addDisposableListener(type: string, handler: XtermListener): IDisposable {
     // TODO: Rename addDisposableEventListener to more easily disambiguate from Dom listener
     this.on(type, handler);
+    let disposed = false;
     return {
       dispose: () => {
-        if (!handler) {
+        if (disposed) {
           // Already disposed
           return;
         }
         this.off(type, handler);
-        handler = null;
+        disposed = true;
       }
     };
   }
diff --git a/src/common/Types.ts b/src/common/Types.ts
index 98cb296d3e..aabe721eb5 100644
--- a/src/common/Types.ts
+++ b/src/common/Types.ts
@@ -3,6 +3,10 @@
  * @license MIT
  */
 
+import { IEventEmitter } from 'xterm';
+
+export type XtermListener = (...args: any[]) => void;
+
 /**
  * A keyboard event interface which does not depend on the DOM, KeyboardEvent implicitly extends
  * this event.
@@ -16,3 +20,16 @@ export interface IKeyboardEvent {
   key: string;
   type: string;
 }
+
+export interface ICircularList<T> extends IEventEmitter {
+  length: number;
+  maxLength: number;
+
+  get(index: number): T | undefined;
+  set(index: number, value: T): void;
+  push(value: T): void;
+  pop(): T | undefined;
+  splice(start: number, deleteCount: number, ...items: T[]): void;
+  trimStart(count: number): void;
+  shiftElements(start: number, count: number, offset: number): void;
+}
diff --git a/src/handlers/AltClickHandler.ts b/src/handlers/AltClickHandler.ts
index aa942f3e72..8226fd96ca 100644
--- a/src/handlers/AltClickHandler.ts
+++ b/src/handlers/AltClickHandler.ts
@@ -3,7 +3,8 @@
  * @license MIT
  */
 
-import { ITerminal, ICircularList, IBufferLine } from '../Types';
+import { ITerminal, IBufferLine } from '../Types';
+import { ICircularList } from '../common/Types';
 import { C0 } from '../common/data/EscapeSequences';
 
 const enum Direction {
diff --git a/src/renderer/Renderer.ts b/src/renderer/Renderer.ts
index a6189efc33..0232887766 100644
--- a/src/renderer/Renderer.ts
+++ b/src/renderer/Renderer.ts
@@ -10,7 +10,7 @@ import { ColorManager } from './ColorManager';
 import { IRenderLayer, IColorSet, IRenderer, IRenderDimensions, ICharacterJoinerRegistry } from './Types';
 import { ITerminal, CharacterJoinerHandler } from '../Types';
 import { LinkRenderLayer } from './LinkRenderLayer';
-import { EventEmitter } from '../EventEmitter';
+import { EventEmitter } from '../common/EventEmitter';
 import { RenderDebouncer } from '../ui/RenderDebouncer';
 import { ScreenDprMonitor } from '../ui/ScreenDprMonitor';
 import { ITheme } from 'xterm';
diff --git a/src/renderer/dom/DomRenderer.ts b/src/renderer/dom/DomRenderer.ts
index b3f69ffcd5..9a2ef46983 100644
--- a/src/renderer/dom/DomRenderer.ts
+++ b/src/renderer/dom/DomRenderer.ts
@@ -6,7 +6,7 @@
 import { IRenderer, IRenderDimensions, IColorSet } from '../Types';
 import { ITerminal, CharacterJoinerHandler } from '../../Types';
 import { ITheme } from 'xterm';
-import { EventEmitter } from '../../EventEmitter';
+import { EventEmitter } from '../../common/EventEmitter';
 import { ColorManager } from '../ColorManager';
 import { RenderDebouncer } from '../../ui/RenderDebouncer';
 import { BOLD_CLASS, ITALIC_CLASS, CURSOR_CLASS, CURSOR_STYLE_BLOCK_CLASS, CURSOR_STYLE_BAR_CLASS, CURSOR_STYLE_UNDERLINE_CLASS, DomRendererRowFactory } from './DomRendererRowFactory';
diff --git a/src/ui/CharMeasure.ts b/src/ui/CharMeasure.ts
index 5ad1de76ae..7d1e5e48af 100644
--- a/src/ui/CharMeasure.ts
+++ b/src/ui/CharMeasure.ts
@@ -4,7 +4,7 @@
  */
 
 import { ICharMeasure, ITerminalOptions } from '../Types';
-import { EventEmitter } from '../EventEmitter';
+import { EventEmitter } from '../common/EventEmitter';
 
 /**
  * Utility class that measures the size of a character. Measurements are done in
diff --git a/src/utils/TestUtils.test.ts b/src/utils/TestUtils.test.ts
index b9bb034822..32a7e9bc03 100644
--- a/src/utils/TestUtils.test.ts
+++ b/src/utils/TestUtils.test.ts
@@ -4,7 +4,8 @@
  */
 
 import { IColorSet, IRenderer, IRenderDimensions, IColorManager } from '../renderer/Types';
-import { IInputHandlingTerminal, IViewport, ICompositionHelper, ITerminal, IBuffer, IBufferSet, IBrowser, ICharMeasure, ISelectionManager, ITerminalOptions, ICircularList, ILinkifier, IMouseHelper, ILinkMatcherOptions, XtermListener, CharacterJoinerHandler, IBufferLine } from '../Types';
+import { IInputHandlingTerminal, IViewport, ICompositionHelper, ITerminal, IBuffer, IBufferSet, IBrowser, ICharMeasure, ISelectionManager, ITerminalOptions, ILinkifier, IMouseHelper, ILinkMatcherOptions, CharacterJoinerHandler, IBufferLine } from '../Types';
+import { ICircularList, XtermListener } from '../common/Types';
 import { Buffer } from '../Buffer';
 import * as Browser from '../shared/utils/Browser';
 import { ITheme, IDisposable, IMarker } from 'xterm';
diff --git a/yarn.lock b/yarn.lock
index 7e28a3c107..f12043f770 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5868,9 +5868,9 @@ typedarray@^0.0.6, typedarray@~0.0.5:
   version "0.0.6"
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
 
-typescript@2.8.3:
-  version "2.8.3"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.8.3.tgz#5d817f9b6f31bb871835f4edf0089f21abe6c170"
+typescript@3.0:
+  version "3.0.3"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.0.3.tgz#4853b3e275ecdaa27f78fda46dc273a7eb7fc1c8"
 
 uglify-es@^3.3.4:
   version "3.3.9"