{ "presets": [ "@babel/preset-react", "@babel/preset-flow" ], "plugins": [ [ "@babel/plugin-proposal-decorators", { "legacy": true } ], ["@babel/plugin-proposal-class-properties", { "loose" : true }], ["@babel/plugin-proposal-optional-chaining"] ], "env": { "development": { "plugins": [ "react-hot-loader/babel" ] }, "test": { "presets": [ [ "@babel/preset-env", { "targets": { "node": "10" } } ], // We need to add this again because it has to run before es2015 "@babel/preset-flow" ] } } }