vue父传子props，怎么设置默认值呢，我的default为什么不行？

Question

vue父传子props，怎么设置默认值呢，我的default为什么不行呢？

父组件 one

        <two :message="ac" :acacacac="aaa"></two>

        

         import two from "./two";

            

        data(){

        return{

            aaa:"",

            ac:"",

        }

    },

    components:{

        two

    },

父组件 two

    <div>

     <div>我是子组件</div>

      {{message}}

      {{acacacac}}

  </div>

 props:{

        message:{

            default:"我是默认值"

        },

        acacacac:{

            default:"我是下一个默认值"

        }

    },

为什么没有效果呢？

Answer 1

题主可以试试ac: undefined有效而aaa: ""无效，表面上看起来似乎有点智障父组件：&nbsp;data() {&nbsp; &nbsp; return {&nbsp; &nbsp; &nbsp; ac: undefined,//有效&nbsp; &nbsp; &nbsp; aaa: ""//无效&nbsp; &nbsp; };&nbsp; }&nbsp;&nbsp;子组件：export default {&nbsp; name: "two",&nbsp; props: {&nbsp; &nbsp; message: {&nbsp; &nbsp; &nbsp; type: String,&nbsp; &nbsp; &nbsp; default: "我是默认值"&nbsp; &nbsp; },&nbsp; &nbsp; acacacac: {&nbsp; &nbsp; &nbsp; type: String,&nbsp; &nbsp; &nbsp; default: "我是下一个默认值"&nbsp; &nbsp; }&nbsp; }};结果：

Answer 2

两种写法。&nbsp; &nbsp; <div>&nbsp; &nbsp; &nbsp;<div>我是子组件</div>&nbsp; &nbsp; &nbsp; {{message}}&nbsp; &nbsp; &nbsp; {{acacacac}}&nbsp; </div>&nbsp;props:{&nbsp; &nbsp; &nbsp; &nbsp; message:{&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; type: String,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; default:"我是默认值"&nbsp; &nbsp; &nbsp; &nbsp; },&nbsp; &nbsp; &nbsp; &nbsp; acacacac:{&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; type: String,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; default:()=>{&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return '默认值'&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; },