Install @babel/plugin-proposal-decorators

package-lock.json

@@ -535,6 +535,26 @@
         "@babel/helper-plugin-utils": "^7.0.0"
       }
     },
+    "@babel/plugin-proposal-decorators": {
+      "version": "7.4.4",
+      "resolved": "https://registry.npmjs.org/@babel/plugin-proposal-decorators/-/plugin-proposal-decorators-7.4.4.tgz",
+      "integrity": "sha512-z7MpQz3XC/iQJWXH9y+MaWcLPNSMY9RQSthrLzak8R8hCj0fuyNk+Dzi9kfNe/JxxlWQ2g7wkABbgWjW36MTcw==",
+      "dev": true,
+      "requires": {
+        "@babel/helper-create-class-features-plugin": "^7.4.4",
+        "@babel/helper-plugin-utils": "^7.0.0",
+        "@babel/plugin-syntax-decorators": "^7.2.0"
+      }
+    },
+    "@babel/plugin-syntax-decorators": {
+      "version": "7.2.0",
+      "resolved": "https://registry.npmjs.org/@babel/plugin-syntax-decorators/-/plugin-syntax-decorators-7.2.0.tgz",
+      "integrity": "sha512-38QdqVoXdHUQfTpZo3rQwqQdWtCn5tMv4uV6r2RMfTqNBuv4ZBhz79SfaQWKTVmxHjeFv/DnXVC/+agHCklYWA==",
+      "dev": true,
+      "requires": {
+        "@babel/helper-plugin-utils": "^7.0.0"
+      }
+    },
     "@babel/plugin-syntax-jsx": {
       "version": "7.2.0",
       "resolved": "https://registry.npmjs.org/@babel/plugin-syntax-jsx/-/plugin-syntax-jsx-7.2.0.tgz",

package.json

@@ -24,6 +24,7 @@
     "@babel/cli": "^7.4.4",
     "@babel/core": "^7.4.4",
     "@babel/plugin-proposal-class-properties": "^7.4.4",
+    "@babel/plugin-proposal-decorators": "^7.4.4",
     "@babel/preset-react": "^7.0.0",
     "@babel/preset-typescript": "^7.3.3",
     "@types/chai": "^4.1.7",