Add support for optional chaining and nullish coalascing

package-lock.json

@@ -533,9 +533,9 @@
 			}
 		},
 		"@babel/plugin-proposal-optional-chaining": {
-			"version": "7.8.3",
-			"resolved": "https://registry.npmjs.org/@babel/plugin-proposal-optional-chaining/-/plugin-proposal-optional-chaining-7.8.3.tgz",
-			"integrity": "sha512-QIoIR9abkVn+seDE3OjA08jWcs3eZ9+wJCKSRgo3WdEU2csFYgdScb+8qHB3+WXsGJD55u+5hWCISI7ejXS+kg==",
+			"version": "7.9.0",
+			"resolved": "https://registry.npmjs.org/@babel/plugin-proposal-optional-chaining/-/plugin-proposal-optional-chaining-7.9.0.tgz",
+			"integrity": "sha512-NDn5tu3tcv4W30jNhmc2hyD5c56G6cXx4TesJubhxrJeCvuuMpttxr0OnNCqbZGhFjLrg+NIhxxC+BK5F6yS3w==",
 			"dev": true,
 			"requires": {
 				"@babel/helper-plugin-utils": "^7.8.3",
@@ -14180,7 +14180,7 @@
 				},
 				"camelcase-keys": {
 					"version": "2.1.0",
-					"resolved": "http://registry.npmjs.org/camelcase-keys/-/camelcase-keys-2.1.0.tgz",
+					"resolved": "https://registry.npmjs.org/camelcase-keys/-/camelcase-keys-2.1.0.tgz",
 					"integrity": "sha1-MIvur/3ygRkFHvodkyITyRuPkuc=",
 					"dev": true,
 					"requires": {
@@ -14190,7 +14190,7 @@
 				},
 				"chalk": {
 					"version": "1.1.3",
-					"resolved": "http://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
+					"resolved": "https://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
 					"integrity": "sha1-qBFcVeSnAv5NFQq9OHKCKn4J/Jg=",
 					"dev": true,
 					"requires": {
@@ -14232,7 +14232,7 @@
 				},
 				"load-json-file": {
 					"version": "1.1.0",
-					"resolved": "http://registry.npmjs.org/load-json-file/-/load-json-file-1.1.0.tgz",
+					"resolved": "https://registry.npmjs.org/load-json-file/-/load-json-file-1.1.0.tgz",
 					"integrity": "sha1-lWkFcI1YtLq0wiYbBPWfMcmTdMA=",
 					"dev": true,
 					"requires": {
@@ -14251,7 +14251,7 @@
 				},
 				"meow": {
 					"version": "3.7.0",
-					"resolved": "http://registry.npmjs.org/meow/-/meow-3.7.0.tgz",
+					"resolved": "https://registry.npmjs.org/meow/-/meow-3.7.0.tgz",
 					"integrity": "sha1-cstmi0JSKCkKu/qFaJJYcwioAfs=",
 					"dev": true,
 					"requires": {
@@ -18737,7 +18737,7 @@
 		},
 		"pinkie-promise": {
 			"version": "2.0.1",
-			"resolved": "http://registry.npmjs.org/pinkie-promise/-/pinkie-promise-2.0.1.tgz",
+			"resolved": "https://registry.npmjs.org/pinkie-promise/-/pinkie-promise-2.0.1.tgz",
 			"integrity": "sha1-ITXW36ejWMBprJsXh3YogihFD/o=",
 			"dev": true,
 			"requires": {
@@ -20228,7 +20228,7 @@
 				},
 				"load-json-file": {
 					"version": "1.1.0",
-					"resolved": "http://registry.npmjs.org/load-json-file/-/load-json-file-1.1.0.tgz",
+					"resolved": "https://registry.npmjs.org/load-json-file/-/load-json-file-1.1.0.tgz",
 					"integrity": "sha1-lWkFcI1YtLq0wiYbBPWfMcmTdMA=",
 					"dev": true,
 					"requires": {
@@ -20241,7 +20241,7 @@
 				},
 				"os-locale": {
 					"version": "1.4.0",
-					"resolved": "http://registry.npmjs.org/os-locale/-/os-locale-1.4.0.tgz",
+					"resolved": "https://registry.npmjs.org/os-locale/-/os-locale-1.4.0.tgz",
 					"integrity": "sha1-IPnxeuKe00XoveWDsT0gCYA8FNk=",
 					"dev": true,
 					"requires": {

package.json

@@ -57,6 +57,8 @@
   "devDependencies": {
     "@babel/cli": "^7.5.0",
     "@babel/core": "^7.5.4",
+    "@babel/plugin-proposal-nullish-coalescing-operator": "^7.8.3",
+    "@babel/plugin-proposal-optional-chaining": "^7.9.0",
     "@babel/plugin-syntax-dynamic-import": "^7.2.0",
     "@babel/preset-env": "^7.5.4",
     "@converse/headless": "file:src/headless",

src/converse-muc-views.js

@@ -761,7 +761,7 @@ converse.plugins.add('converse-muc-views', {
                 const actors_per_state = this.model.csn.toJSON();
                 const message = converse.CHAT_STATES.reduce((result, state) => {
                     const existing_actors = actors_per_state[state];
-                    if (!existing_actors) {
+                    if (!(existing_actors?.length)) {
                         return result;
                     }
                     const actors = existing_actors

webpack.common.js

@@ -100,7 +100,11 @@ module.exports = {
                             }
                         }]
                     ],
-                    plugins: ['@babel/plugin-syntax-dynamic-import']
+                    plugins: [
+                        '@babel/plugin-proposal-nullish-coalescing-operator',
+                        '@babel/plugin-proposal-optional-chaining',
+                        '@babel/plugin-syntax-dynamic-import'
+                    ]
                 }
             }
         }, {