From 322951bdc06262f49212bacdbd7e440017c73411 Mon Sep 17 00:00:00 2001
From: Bryan Housel <bryan@mapbox.com>
Date: Sat, 2 Mar 2019 18:18:44 -0500
Subject: [PATCH] Add polyfill for `Object.getOwnPropertySymbols` for sinon
 (closes #6001)

---
 package.json              | 2 +-
 test/spec/spec_helpers.js | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/package.json b/package.json
index ce35d305b..5702ab97e 100644
--- a/package.json
+++ b/package.json
@@ -85,7 +85,7 @@
     "rollup-plugin-node-resolve": "^4.0.0",
     "shelljs": "^0.8.0",
     "shx": "^0.3.0",
-    "sinon": "^7.2.4",
+    "sinon": "^7.2.6",
     "sinon-chai": "^3.1.0",
     "smash": "0.0",
     "svg-sprite": "1.5.0",
diff --git a/test/spec/spec_helpers.js b/test/spec/spec_helpers.js
index 2a70210dd..1db452d4e 100644
--- a/test/spec/spec_helpers.js
+++ b/test/spec/spec_helpers.js
@@ -38,6 +38,12 @@ expect = chai.expect;
 
 window.d3 = iD.d3;   // TODO: remove
 
+// Object.getOwnPropertySymbols polyfill (For PhantomJS / IE11) - #6001
+if (!Object.getOwnPropertySymbols) {
+  Object.defineProperty(Object.prototype, 'getOwnPropertySymbols', {
+    value: function() { return []; }
+  });
+}
 
 // Array.find polyfill (For PhantomJS / IE11)
 // https://tc39.github.io/ecma262/#sec-array.prototype.find