Default state after run of make build-js
$ npm list --depth=0
lektor@0.0.0 /home/nemo/workspace/lektor/lektor/admin
├── babel@6.23.0
├── babel-core@6.25.0
├── babel-loader@6.4.1
├── babel-plugin-istanbul@2.0.3
├── babel-plugin-transform-object-rest-spread@6.23.0
├── babel-preset-es2015@6.24.1
├── babel-preset-react@6.24.1
├── babel-register@6.24.1
├── bootstrap@3.3.7
├── chai@3.5.0
├── css-loader@0.9.1
├── event-source-polyfill@0.0.5
├── extract-text-webpack-plugin@0.3.8
├── file-loader@0.8.5
├── font-awesome@4.7.0
├── history@1.17.0
├── jquery@2.2.4
├── jsdomify@2.2.0
├── json-loader@0.5.4
├── less@1.7.5
├── less-loader@0.7.8
├── mocha@3.4.2
├── native-promise-only@0.7.6-a
├── nyc@8.4.0
├── querystring@0.2.0
├── react@15.6.1
├── react-addons-test-utils@15.6.0
├── react-addons-update@15.6.0
├── react-dom@15.6.1
├── react-router@2.8.1
├── standard@10.0.2
├── style-loader@0.8.3
├── url-loader@0.5.9
└── webpack@1.15.0
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
state after changing package.json to use babel=5.8.38, and then make build-js
$ npm list --depth=0
lektor@0.0.0 /home/nemo/workspace/lektor/lektor/admin
├── babel@5.8.38
├── babel-core@6.25.0
├── babel-loader@6.4.1
├── babel-plugin-istanbul@2.0.3
├── babel-plugin-transform-object-rest-spread@6.23.0
├── babel-preset-es2015@6.24.1
├── babel-preset-react@6.24.1
├── babel-register@6.24.1
├── bootstrap@3.3.7
├── chai@3.5.0
├── css-loader@0.9.1
├── event-source-polyfill@0.0.5
├── extract-text-webpack-plugin@0.3.8
├── file-loader@0.8.5
├── font-awesome@4.7.0
├── history@1.17.0
├── jquery@2.2.4
├── jsdomify@2.2.0
├── json-loader@0.5.4
├── less@1.7.5
├── less-loader@0.7.8
├── mocha@3.4.2
├── native-promise-only@0.7.6-a
├── nyc@8.4.0
├── querystring@0.2.0
├── react@15.6.1
├── react-addons-test-utils@15.6.0
├── react-addons-update@15.6.0
├── react-dom@15.6.1
├── react-router@2.8.1
├── standard@10.0.2
├── style-loader@0.8.3
├── url-loader@0.5.9
└── webpack@1.15.0
++++++++++++++++++++++++++++++++++++++++++++++++++++++++