i have been having issue on week now. code runs fine in browser , no errors, when run mocha test , error of missing class properties transform . installed via npm , deleted packages , re-installed them still nothing. have read numerous posts on here (i.e. error: missing class properties transform ) , still come error. missing here? help. webpack.config.js: ... module: { loaders: [ { test: /\.(js|jsx)$/, include: [ path.resolve(__dirname, "public/app") ], exclude: /node_modules/, loaders: [ 'react-hot', 'babel?presets[]=react,presets[]=es2015,presets[]=stage-0' ], loader: 'babel', query: { "plugins": ['transform-decorators-legacy'] } }, { test: /\.json?$/, loader: 'json' },