From 7525c57688ad98c9c8ef39c7d6b5bd0c73093f64 Mon Sep 17 00:00:00 2001
From: William Wall <wwall@caci.com>
Date: Wed, 19 Sep 2018 14:39:10 -0600
Subject: [PATCH] Check the type of the source before using it

This satisfies tsc in addition to making the class more defensive
against source types that it does not support.
---
 src/ol/renderer/webgl/TileLayer.js | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/ol/renderer/webgl/TileLayer.js b/src/ol/renderer/webgl/TileLayer.js
index f263dddc52..fc07e504a0 100644
--- a/src/ol/renderer/webgl/TileLayer.js
+++ b/src/ol/renderer/webgl/TileLayer.js
@@ -7,6 +7,7 @@
 import LayerType from '../../LayerType.js';
 import TileRange from '../../TileRange.js';
 import TileState from '../../TileState.js';
+import TileSource from '../../source/Tile.js';
 import {numberSafeCompareFunction} from '../../array.js';
 import {createEmpty, intersects} from '../../extent.js';
 import {roundUpToPowerOfTwo} from '../../math.js';
@@ -152,6 +153,10 @@ class WebGLTileLayerRenderer extends WebGLLayerRenderer {
 
     const tileLayer = /** @type {import("../../layer/Tile.js").default} */ (this.getLayer());
     const tileSource = tileLayer.getSource();
+    if (!(tileSource instanceof TileSource)) {
+      return true;
+    }
+
     const tileGrid = tileSource.getTileGridForProjection(projection);
     const z = tileGrid.getZForResolution(viewState.resolution);
     const tileResolution = tileGrid.getResolution(z);