vue Cannot read property 'company_name' of

Question

<el-input class="pull-left" v-model="params.company_name"></el-input>

我定义的

data () {

      return {

        params: {

          company_name: '',

          site_name: '',

          domain: '',

          adress: '',

          registered_assets: '',

          legal: '',

          type: 1,

          reason: ''

        }

      }

    },

运行出现错误   Cannot read property 'company_name' of undefined  怎么解决？？