From a5ddac3b5a09d39cd31329bf93436472d55d64d8 Mon Sep 17 00:00:00 2001
From: James Hamilton <james@thechipfactory.co.uk>
Date: Sun, 25 Jul 2021 08:06:34 +0900
Subject: [PATCH] cast type of else statement - might work better with type
 guard

---
 src/source/raster_dem_tile_worker_source.ts | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/source/raster_dem_tile_worker_source.ts b/src/source/raster_dem_tile_worker_source.ts
index f56a6b5e10..1b5696a8fe 100644
--- a/src/source/raster_dem_tile_worker_source.ts
+++ b/src/source/raster_dem_tile_worker_source.ts
@@ -1,6 +1,5 @@
 import DEMData from '../data/dem_data';
 import {RGBAImage} from '../util/image';
-import window from '../util/window';
 
 import type Actor from '../util/actor';
 import type {
@@ -8,7 +7,6 @@ import type {
     WorkerDEMTileCallback,
     TileParameters
 } from './worker_source';
-const {ImageBitmap} = window;
 
 class RasterDEMTileWorkerSource {
     actor: Actor;
@@ -25,7 +23,7 @@ class RasterDEMTileWorkerSource {
     loadTile(params: WorkerDEMTileParameters, callback: WorkerDEMTileCallback) {
         const {uid, encoding, rawImageData} = params;
         // Main thread will transfer ImageBitmap if offscreen decode with OffscreenCanvas is supported, else it will transfer an already decoded image.
-        const imagePixels = (ImageBitmap && rawImageData instanceof ImageBitmap) ? this.getImageData(rawImageData) : rawImageData;
+        const imagePixels = (ImageBitmap && rawImageData instanceof ImageBitmap) ? this.getImageData(rawImageData) : rawImageData as RGBAImage;
         const dem = new DEMData(uid, imagePixels, encoding);
         this.loaded = this.loaded || {};
         this.loaded[uid] = dem;