diff --git a/src/renderer/atlas/DynamicCharAtlas.ts b/src/browser/renderer/atlas/DynamicCharAtlas.ts
similarity index 95%
rename from src/renderer/atlas/DynamicCharAtlas.ts
rename to src/browser/renderer/atlas/DynamicCharAtlas.ts
index 9af79e01e..d591c173b 100644
--- a/src/renderer/atlas/DynamicCharAtlas.ts
+++ b/src/browser/renderer/atlas/DynamicCharAtlas.ts
@@ -3,10 +3,9 @@
  * @license MIT
  */
 
-import { ICharAtlasConfig } from './Types';
 import { DIM_OPACITY, INVERTED_DEFAULT_COLOR } from 'browser/renderer/atlas/Constants';
-import { IGlyphIdentifier } from 'browser/renderer/atlas/Types';
-import { BaseCharAtlas } from '../../browser/renderer/atlas/BaseCharAtlas';
+import { IGlyphIdentifier, ICharAtlasConfig } from 'browser/renderer/atlas/Types';
+import { BaseCharAtlas } from 'browser/renderer/atlas/BaseCharAtlas';
 import { DEFAULT_ANSI_COLORS } from 'browser/ColorManager';
 import { LRUMap } from 'browser/renderer/atlas/LRUMap';
 import { isFirefox, isSafari } from 'common/Platform';
@@ -90,12 +89,12 @@ export class DynamicCharAtlas extends BaseCharAtlas {
     // The canvas needs alpha because we use clearColor to convert the background color to alpha.
     // It might also contain some characters with transparent backgrounds if allowTransparency is
     // set.
-    this._cacheCtx = this._cacheCanvas.getContext('2d', {alpha: true});
+    this._cacheCtx = throwIfFalsy(this._cacheCanvas.getContext('2d', {alpha: true}));
 
     const tmpCanvas = document.createElement('canvas');
     tmpCanvas.width = this._config.scaledCharWidth;
     tmpCanvas.height = this._config.scaledCharHeight;
-    this._tmpCtx = tmpCanvas.getContext('2d', {alpha: this._config.allowTransparency});
+    this._tmpCtx = throwIfFalsy(tmpCanvas.getContext('2d', {alpha: this._config.allowTransparency}));
 
     this._width = Math.floor(TEXTURE_WIDTH / this._config.scaledCharWidth);
     this._height = Math.floor(TEXTURE_HEIGHT / this._config.scaledCharHeight);
@@ -145,7 +144,7 @@ export class DynamicCharAtlas extends BaseCharAtlas {
         index = this._cacheMap.size;
       } else {
         // we're out of space, so our call to set will delete this item
-        index = this._cacheMap.peek().index;
+        index = this._cacheMap.peek()!.index;
       }
       const cacheValue = this._drawToCache(glyph, index);
       this._cacheMap.set(glyphKey, cacheValue);
@@ -187,7 +186,7 @@ export class DynamicCharAtlas extends BaseCharAtlas {
     const cacheX = this._toCoordinateX(cacheValue.index);
     const cacheY = this._toCoordinateY(cacheValue.index);
     ctx.drawImage(
-      cacheValue.inBitmap ? this._bitmap : this._cacheCanvas,
+      cacheValue.inBitmap ? this._bitmap! : this._cacheCanvas,
       cacheX,
       cacheY,
       this._config.scaledCharWidth,
@@ -367,3 +366,10 @@ function clearColor(imageData: ImageData, color: IColor): boolean {
   }
   return isEmpty;
 }
+
+export function throwIfFalsy<T>(value: T | undefined | null): T {
+  if (!value) {
+    throw new Error('value must not be falsy');
+  }
+  return value;
+}
diff --git a/src/browser/renderer/atlas/Types.d.ts b/src/browser/renderer/atlas/Types.d.ts
index fd5b596cb..0724b163f 100644
--- a/src/browser/renderer/atlas/Types.d.ts
+++ b/src/browser/renderer/atlas/Types.d.ts
@@ -3,6 +3,9 @@
  * @license MIT
  */
 
+import { FontWeight } from 'common/services/Services';
+import { IColorSet } from 'browser/Types';
+
 export interface IGlyphIdentifier {
   chars: string;
   code: number;
@@ -12,3 +15,15 @@ export interface IGlyphIdentifier {
   dim: boolean;
   italic: boolean;
 }
+
+export interface ICharAtlasConfig {
+  devicePixelRatio: number;
+  fontSize: number;
+  fontFamily: string;
+  fontWeight: FontWeight;
+  fontWeightBold: FontWeight;
+  scaledCharWidth: number;
+  scaledCharHeight: number;
+  allowTransparency: boolean;
+  colors: IColorSet;
+}
diff --git a/src/renderer/atlas/CharAtlasCache.ts b/src/renderer/atlas/CharAtlasCache.ts
index f9bd68a1f..ec66b67a7 100644
--- a/src/renderer/atlas/CharAtlasCache.ts
+++ b/src/renderer/atlas/CharAtlasCache.ts
@@ -6,8 +6,8 @@
 import { ITerminal } from '../../Types';
 import { generateConfig, configEquals } from './CharAtlasUtils';
 import { BaseCharAtlas } from 'browser/renderer/atlas/BaseCharAtlas';
-import { DynamicCharAtlas } from './DynamicCharAtlas';
-import { ICharAtlasConfig } from './Types';
+import { DynamicCharAtlas } from '../../browser/renderer/atlas/DynamicCharAtlas';
+import { ICharAtlasConfig } from 'browser/renderer/atlas/Types';
 import { IColorSet } from 'browser/Types';
 
 interface ICharAtlasCacheEntry {
diff --git a/src/renderer/atlas/CharAtlasUtils.ts b/src/renderer/atlas/CharAtlasUtils.ts
index ee787a7ba..da067f520 100644
--- a/src/renderer/atlas/CharAtlasUtils.ts
+++ b/src/renderer/atlas/CharAtlasUtils.ts
@@ -4,7 +4,7 @@
  */
 
 import { ITerminal } from '../../Types';
-import { ICharAtlasConfig } from './Types';
+import { ICharAtlasConfig } from 'browser/renderer/atlas/Types';
 import { DEFAULT_COLOR } from 'common/buffer/Constants';
 import { IColorSet } from 'browser/Types';
 
diff --git a/src/renderer/atlas/Types.d.ts b/src/renderer/atlas/Types.d.ts
deleted file mode 100644
index f717381c8..000000000
--- a/src/renderer/atlas/Types.d.ts
+++ /dev/null
@@ -1,19 +0,0 @@
-/**
- * Copyright (c) 2017 The xterm.js authors. All rights reserved.
- * @license MIT
- */
-
-import { FontWeight } from 'xterm';
-import { IColorSet } from 'browser/Types';
-
-export interface ICharAtlasConfig {
-  devicePixelRatio: number;
-  fontSize: number;
-  fontFamily: string;
-  fontWeight: FontWeight;
-  fontWeightBold: FontWeight;
-  scaledCharWidth: number;
-  scaledCharHeight: number;
-  allowTransparency: boolean;
-  colors: IColorSet;
-}