element-ui 常用表单校验 配置

<el-form :model="form" :rules="rules" ref="form" label-width="100px">
         <el-form-item label="活动名称" prop="name">
                     <el-input v-model="form.name"></el-input>
         </el-form-item>
</el-form>

　　　rules: {
        name:[
                  {
                      required: true,
                      message: '请输入活动名称',
                      trigger: 'blur'
                   },{
                      pattern: /^[0-9 a-z A-Z]*$/, 
                      message: "只允许输入数字或字母或数字与字母的组合" 
                   },{
                      min: 1,
                      max: 20,
                      message: "长度在 1 到 20 个字符"
                   }
           ],
       },