From 27a92a5c894ff01566c7ddce84957334b78809da Mon Sep 17 00:00:00 2001
From: "J. Ryan Stinnett" <jryans@gmail.com>
Date: Mon, 8 Feb 2021 16:36:49 +0000
Subject: [PATCH] Add RegExp dotAll feature test

As mentioned in
https://github.com/vector-im/element-web/issues/16020#issuecomment-774384598,
we're depending on the `dotAll` / `s` regex feature. This adds a test so
browsers without this see an error screen.
---
 src/vector/index.ts | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/vector/index.ts b/src/vector/index.ts
index b3e29bc382..21aacaf69e 100644
--- a/src/vector/index.ts
+++ b/src/vector/index.ts
@@ -45,14 +45,20 @@ function checkBrowserFeatures() {
         return false;
     }
 
-    // custom checks atop Modernizr because it doesn't have ES2018/ES2019 checks in it for some features we depend on,
-    // Modernizr requires rules to be lowercase with no punctuation:
-    // ES2018: http://www.ecma-international.org/ecma-262/9.0/#sec-promise.prototype.finally
+    // Custom checks atop Modernizr because it doesn't have ES2018/ES2019 checks
+    // in it for some features we depend on.
+    // Modernizr requires rules to be lowercase with no punctuation.
+    // ES2018: http://262.ecma-international.org/9.0/#sec-promise.prototype.finally
     window.Modernizr.addTest("promiseprototypefinally", () =>
-        window.Promise && window.Promise.prototype && typeof window.Promise.prototype.finally === "function");
-    // ES2019: http://www.ecma-international.org/ecma-262/10.0/#sec-object.fromentries
+        typeof window.Promise?.prototype?.finally === "function");
+    // ES2018: https://262.ecma-international.org/9.0/#sec-get-regexp.prototype.dotAll
+    window.Modernizr.addTest("regexpdotall", () => (
+        window.RegExp?.prototype &&
+        !!Object.getOwnPropertyDescriptor(window.RegExp.prototype, "dotAll")?.get
+    ));
+    // ES2019: http://262.ecma-international.org/10.0/#sec-object.fromentries
     window.Modernizr.addTest("objectfromentries", () =>
-        window.Object && typeof window.Object.fromEntries === "function");
+        typeof window.Object?.fromEntries === "function");
 
     const featureList = Object.keys(window.Modernizr);