element某个字段根据特殊条件判断是否为必填项

 <el-form :model="ruleForm"
	:rules="rules"
    ref="ruleForm"
    label-width="100px"  
> 
 	<el-form-item label="项目来源" prop="projectSource" 
 	  :rules="projectSourceIsMust?rules.projectSource:[
 	  	{
     required: false, message: '请输入项目来源', trigger: 'blur' },
         {
      max: 1000, message: '项目来源不能超过1000位', trigger: 'blur'}]">
        <el-input type="textarea" :autosize="{ minRows: 3}" v-model="ruleForm.projectSource"  ></el-input>
     </el-form-item>
</el-form>

projectSourceIsMust为特殊条件，如果为true,则为必填校验规则，否则就是required: false

data中数据定义：

 data () {
     
 	return {
     
 		 ruleForm: {
     
 		 	projectSource:''
 		 }，
 		 rules: {
     
 		 	projectSource: [
            {
     required: true, message: '请输入项目来源', trigger: 'blur' },
            {
      max: 1000, message: '项目来源不能超过1000位', trigger: 'blur' },]
 		 }
 	}
 }