El form item regular verification

      <el-form-item label=" Name of commodity " prop="name">
        <el-input type="text" v-model.trim="param.name" style="width:640px" @change="handleChange" maxlength="30" ></el-input>
      </el-form-item>

rules:{
    
   name: [
    {
    
      validator: (rule, value, callback) => {
    
        console.log(value, 'lail ')
        if (!value) {
    
          callback(new Error(' Please enter the product name '))
        } else {
    
          let chinese = []
          let noChinese = []
          chinese = value.split('').filter(item => {
    
            return /^[\u4e00-\u9fa5]{0,}$/.test(item) === true
          })
          noChinese = value.split('').filter(item => {
    
            return /^[\u4e00-\u9fa5]{0,}$/.test(item) !== true
          })
          var num = chinese.length * 2 + noChinese.length
          console.log(num)
          if (num < 4 || num > 30) {
    
            callback(new Error(' Please enter 2 To 15 The Chinese characters .'))
          }
        }
      },
      trigger: 'blur',
      required: true
    }
  ],
}