Temporary workaround for what seems like a yarn2nix issue

package.json

@@ -8,6 +8,10 @@
   "license": "WTFPL OR CC0-1.0",
   "bin": "bin/matrix-rooms",
   "dependencies": {
+    "@babel/core": "^7.5.5",
+    "@babel/plugin-transform-flow-strip-types": "^7.4.4",
+    "@babel/preset-env": "^7.5.5",
+    "@babel/preset-react": "^7.0.0",
     "@joepie91/express-react-views": "^1.0.1",
     "@modular-matrix/autodiscover-client-configuration": "^1.0.0",
     "bhttp": "^1.2.4",

yarn.lock

@@ -9,7 +9,7 @@
   dependencies:
     "@babel/highlight" "^7.0.0"
 
-"@babel/core@^7.0.0":
+"@babel/core@^7.0.0", "@babel/core@^7.5.5":
   version "7.5.5"
   resolved "https://registry.yarnpkg.com/@babel/core/-/core-7.5.5.tgz#17b2686ef0d6bc58f963dddd68ab669755582c30"
   integrity sha512-i4qoSr2KTtce0DmkuuQBV4AuQgGPUcPXMr9L5MyYAtk06z068lQ10a4O009fe5OB/DfNV+h+qqT7ddNV8UnRjg==
@@ -408,7 +408,7 @@
     "@babel/helper-builder-binary-assignment-operator-visitor" "^7.1.0"
     "@babel/helper-plugin-utils" "^7.0.0"
 
-"@babel/plugin-transform-flow-strip-types@^7.0.0":
+"@babel/plugin-transform-flow-strip-types@^7.0.0", "@babel/plugin-transform-flow-strip-types@^7.4.4":
   version "7.4.4"
   resolved "https://registry.yarnpkg.com/@babel/plugin-transform-flow-strip-types/-/plugin-transform-flow-strip-types-7.4.4.tgz#d267a081f49a8705fc9146de0768c6b58dccd8f7"
   integrity sha512-WyVedfeEIILYEaWGAUWzVNyqG4sfsNooMhXWsu/YzOvVGcsnPb5PguysjJqI3t3qiaYj0BR8T2f5njdjTGe44Q==
@@ -611,7 +611,7 @@
     "@babel/helper-regex" "^7.4.4"
     regexpu-core "^4.5.4"
 
-"@babel/preset-env@^7.0.0":
+"@babel/preset-env@^7.0.0", "@babel/preset-env@^7.5.5":
   version "7.5.5"
   resolved "https://registry.yarnpkg.com/@babel/preset-env/-/preset-env-7.5.5.tgz#bc470b53acaa48df4b8db24a570d6da1fef53c9a"
   integrity sha512-GMZQka/+INwsMz1A5UEql8tG015h5j/qjptpKY2gJ7giy8ohzU710YciJB5rcKsWGWHiW3RUnHib0E5/m3Tp3A==