Cannot read property 'replace' of undefined
at /Users/.../node_modules/webpack/lib/NormalModuleFactory.js:106:27
at /Users/.../node_modules/webpack/lib/NormalModuleFactory.js:59:4
at applyPluginsAsyncWaterfall (/Users/.../node_modules/webpack/lib/NormalModuleFactory.js:236:4)
Cannot read property 'replace' of undefined at /Users/.../node_modules/webpack/lib/NormalModuleFactory.js:106:27 at /Users/.../node_modules/webpack/lib/NormalModuleFactory.js:59:4 at applyPluginsAsyncWaterfall (/Users/.../node_modules/webpack/lib/NormalModuleFactory.js:236:4)