From a44aaf023fd99c22df1df12be3175720694b51fb Mon Sep 17 00:00:00 2001
From: Molly Lloyd <molly@mapbox.com>
Date: Mon, 2 Oct 2017 18:01:10 -0700
Subject: [PATCH] follow new linting rule

---
 src/source/raster_dem_tile_source.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/source/raster_dem_tile_source.js b/src/source/raster_dem_tile_source.js
index a39908f24a9..5d94ddcf5f9 100644
--- a/src/source/raster_dem_tile_source.js
+++ b/src/source/raster_dem_tile_source.js
@@ -1,6 +1,7 @@
 // @flow
 
 const ajax = require('../util/ajax');
+const util = require('../util/util');
 const Evented = require('../util/evented');
 const normalizeURL = require('../util/mapbox').normalizeTileURL;
 const browser = require('../util/browser');
@@ -19,7 +20,7 @@ class RasterDEMTileSource extends RasterTileSource implements Source {
         super(id, options, dispatcher, eventedParent);
         this.type = 'raster-dem';
         this.maxzoom = 15;
-        this._options = Object.assign({}, options);
+        this._options = util.extend({}, options);
     }
 
     serialize() {