Introduce Disposable abstract class

src/Buffer.ts

@@ -6,7 +6,7 @@
 import { CircularList } from './utils/CircularList';
 import { LineData, CharData, ITerminal, IBuffer } from './Types';
 import { EventEmitter } from './EventEmitter';
-import { IDisposable, IMarker } from 'xterm';
+import { IMarker } from 'xterm';
 
 export const DEFAULT_ATTR = (0 << 18) | (257 << 9) | (256 << 0);
 export const CHAR_DATA_ATTR_INDEX = 0;
@@ -320,7 +320,7 @@ export class Buffer implements IBuffer {
   public addMarker(y: number): Marker {
     const marker = new Marker(y);
     this.markers.push(marker);
-    marker.disposables.push(this.lines.addDisposableListener('trim', amount => {
+    marker.register(this.lines.addDisposableListener('trim', amount => {
       marker.line -= amount;
       // The marker should be disposed when the line is trimmed from the buffer
       if (marker.line < 0) {
@@ -342,7 +342,6 @@ export class Marker extends EventEmitter implements IMarker {
 
   private _id: number = Marker._nextId++;
   public isDisposed: boolean = false;
-  public disposables: IDisposable[] = [];
 
   public get id(): number { return this._id; }
 
@@ -357,8 +356,7 @@ export class Marker extends EventEmitter implements IMarker {
       return;
     }
     this.isDisposed = true;
-    this.disposables.forEach(d => d.dispose());
+    super.dispose();
-    this.disposables.length = 0;
     this.emit('dispose');
   }
 }

src/EventEmitter.ts

@@ -5,11 +5,13 @@
 
 import { XtermListener } from './Types';
 import { IEventEmitter, IDisposable } from 'xterm';
+import { Disposable } from './common/Lifecycle';
 
-export class EventEmitter implements IEventEmitter, IDisposable {
+export class EventEmitter extends Disposable implements IEventEmitter, IDisposable {
   private _events: {[type: string]: XtermListener[]};
 
   constructor() {
+    super();
     // Restore the previous events if available, this will happen if the
     // constructor is called multiple times on the same object (terminal reset).
     this._events = this._events || {};
@@ -26,6 +28,7 @@ export class EventEmitter implements IEventEmitter, IDisposable {
    * @param handler The handler for the listener.
    */
   public addDisposableListener(type: string, handler: XtermListener): IDisposable {
+    // TODO: Rename addDisposableEventListener to more easily disambiguate from Dom listener
     this.on(type, handler);
     return {
       dispose: () => {

src/Terminal.ts

@@ -113,8 +113,6 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
   public element: HTMLElement;
   public screenElement: HTMLElement;
 
-  private _disposables: IDisposable[];
-
   /**
    * The HTMLElement that the terminal is created in, set by Terminal.open.
    */
@@ -252,8 +250,6 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
   }
 
   private _setup(): void {
-    this._disposables = [];
-
     Object.keys(DEFAULT_OPTIONS).forEach((key) => {
       if (this.options[key] == null) {
         this.options[key] = DEFAULT_OPTIONS[key];
@@ -688,7 +684,7 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
     this.on('dprchange', () => this.renderer.onWindowResize(window.devicePixelRatio));
     // dprchange should handle this case, we need this as well for browsers that don't support the
     // matchMedia query.
-    this._disposables.push(Dom.addDisposableDomListener(window, 'resize', () => this.renderer.onWindowResize(window.devicePixelRatio)));
+    this.register(Dom.addDisposableDomListener(window, 'resize', () => this.renderer.onWindowResize(window.devicePixelRatio)));
     this.charMeasure.on('charsizechanged', () => this.renderer.onCharSizeChanged());
     this.renderer.on('resize', (dimensions) => this.viewport.syncScrollArea());
 

src/common/Lifecycle.ts

@@ -0,0 +1,22 @@
+/**
+ * Copyright (c) 2018 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { IDisposable } from 'xterm';
+
+export abstract class Disposable implements IDisposable {
+  protected _disposables: IDisposable[] = [];
+
+  constructor() {
+  }
+
+  public dispose(): void {
+    this._disposables.forEach(d => d.dispose());
+    this._disposables.length = 0;
+  }
+
+  public register<T extends IDisposable>(t: T): void {
+    this._disposables.push(t);
+  }
+}