From 619297202bbcc0c07e5a60a0f9c2804080bbc621 Mon Sep 17 00:00:00 2001
From: Martin Kraft <martin@upspin.org>
Date: Wed, 26 Jun 2019 15:13:28 -0400
Subject: [PATCH] Adds optional chaining. (#869)

---
 babel.config.js                  |  1 +
 package-lock.json                | 21 ++++++++++++++++++++-
 package.json                     |  1 +
 src/selectors/entities/groups.js |  4 ++--
 4 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/babel.config.js b/babel.config.js
index a132349f2..aaea5532f 100644
--- a/babel.config.js
+++ b/babel.config.js
@@ -18,6 +18,7 @@ module.exports = {
     plugins: [
         '@babel/transform-flow-comments',
         '@babel/proposal-class-properties',
+        '@babel/plugin-proposal-optional-chaining',
         ['module-resolver', {
             root: ['./src', '.'],
         }],
diff --git a/package-lock.json b/package-lock.json
index b4d2b5c9b..2980c17d6 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -451,6 +451,16 @@
         "@babel/plugin-syntax-optional-catch-binding": "^7.2.0"
       }
     },
+    "@babel/plugin-proposal-optional-chaining": {
+      "version": "7.2.0",
+      "resolved": "https://registry.npmjs.org/@babel/plugin-proposal-optional-chaining/-/plugin-proposal-optional-chaining-7.2.0.tgz",
+      "integrity": "sha512-ea3Q6edZC/55wEBVZAEz42v528VulyO0eir+7uky/sT4XRcdkWJcFi1aPtitTlwUzGnECWJNExWww1SStt+yWw==",
+      "dev": true,
+      "requires": {
+        "@babel/helper-plugin-utils": "^7.0.0",
+        "@babel/plugin-syntax-optional-chaining": "^7.2.0"
+      }
+    },
     "@babel/plugin-proposal-unicode-property-regex": {
       "version": "7.4.4",
       "resolved": "https://registry.npmjs.org/@babel/plugin-proposal-unicode-property-regex/-/plugin-proposal-unicode-property-regex-7.4.4.tgz",
@@ -507,6 +517,15 @@
         "@babel/helper-plugin-utils": "^7.0.0"
       }
     },
+    "@babel/plugin-syntax-optional-chaining": {
+      "version": "7.2.0",
+      "resolved": "https://registry.npmjs.org/@babel/plugin-syntax-optional-chaining/-/plugin-syntax-optional-chaining-7.2.0.tgz",
+      "integrity": "sha512-HtGCtvp5Uq/jH/WNUPkK6b7rufnCPLLlDAFN7cmACoIjaOOiXxUt3SswU5loHqrhtqTsa/WoLQ1OQ1AGuZqaWA==",
+      "dev": true,
+      "requires": {
+        "@babel/helper-plugin-utils": "^7.0.0"
+      }
+    },
     "@babel/plugin-transform-arrow-functions": {
       "version": "7.2.0",
       "resolved": "https://registry.npmjs.org/@babel/plugin-transform-arrow-functions/-/plugin-transform-arrow-functions-7.2.0.tgz",
@@ -9844,7 +9863,7 @@
     },
     "serialize-error": {
       "version": "2.1.0",
-      "resolved": "http://registry.npmjs.org/serialize-error/-/serialize-error-2.1.0.tgz",
+      "resolved": "https://registry.npmjs.org/serialize-error/-/serialize-error-2.1.0.tgz",
       "integrity": "sha1-ULZ51WNc34Rme9yOWa9OW4HV9go="
     },
     "serialize-javascript": {
diff --git a/package.json b/package.json
index 18048c9ca..749e15969 100644
--- a/package.json
+++ b/package.json
@@ -31,6 +31,7 @@
     "@babel/cli": "7.4.4",
     "@babel/core": "7.4.5",
     "@babel/plugin-proposal-class-properties": "7.4.4",
+    "@babel/plugin-proposal-optional-chaining": "^7.2.0",
     "@babel/plugin-transform-flow-comments": "7.4.4",
     "@babel/preset-env": "7.2.0",
     "@babel/register": "7.4.4",
diff --git a/src/selectors/entities/groups.js b/src/selectors/entities/groups.js
index 15c721763..50d432137 100644
--- a/src/selectors/entities/groups.js
+++ b/src/selectors/entities/groups.js
@@ -46,9 +46,9 @@ export function getGroupMembers(state, id) {
     return groupMemberData.members;
 }
 
-const teamGroupIDs = (state, teamID) => state.entities.teams.groupsAssociatedToTeam[teamID].ids || [];
+const teamGroupIDs = (state, teamID) => state.entities.teams.groupsAssociatedToTeam[teamID]?.ids || [];
 
-const channelGroupIDs = (state, channelID) => state.entities.channels.groupsAssociatedToChannel[channelID].ids || [];
+const channelGroupIDs = (state, channelID) => state.entities.channels.groupsAssociatedToChannel[channelID]?.ids || [];
 
 const getTeamGroupIDSet = createSelector(
     teamGroupIDs,