[3260] RangeError: Invalid status code: undefined

when i use 'npm run build' and 'npm start'. the package.json had config

  "config": {
    "nuxt": {
      "host": "0.0.0.0",
      "port": 8080
    }
  },

visit 127.0.0.1:8080 the server responsed:

RangeError: Invalid status code: undefined
    at ServerResponse.writeHead (_http_server.js:190:11)
    at ServerResponse.writeHead (/Users/benson/Desktop/mall/node_modules/on-headers/index.js:55:19)
    at ServerResponse._implicitHeader (_http_server.js:181:8)
    at ServerResponse.end (/Users/benson/Desktop/mall/node_modules/compression/index.js:103:14)
    at sendResponse (/Users/benson/Desktop/mall/node_modules/nuxt/lib/core/middleware/error.js:24:9)
    at Renderer.errorMiddleware (/Users/benson/Desktop/mall/node_modules/nuxt/lib/core/middleware/error.js:47:5)
    at call (/Users/benson/Desktop/mall/node_modules/connect/index.js:235:7)
    at next (/Users/benson/Desktop/mall/node_modules/connect/index.js:183:5)
    at Renderer.nuxtMiddleware (/Users/benson/Desktop/mall/node_modules/nuxt/lib/core/middleware/nuxt.js:110:5)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)