element-ui校验表单项为数字校验

html页面部分

<el-form ref="form" :model="form" label-width="200px">  <el-form-item prop="num">    <el-input v-model="form.num" ></el-input>  </el-form-item></el-form>

js实现部分 

export default {  data() {    var checkNum = (rule, value, callback) => {      console.log("value", value - 0);      if (isNaN(value)) {        return callback("请输入数字");      }      return callback();    },    return {      rules:{        num: [          { required: true, message: "请输入数字", trigger: "blur" },          { validator: checkNum, trigger: "blur"}        ]      }    }  }}