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Javascript Vuejs TypeError:无法读取属性';占位符';“未定义”的定义;_Javascript_Vue.js_Vuejs2 - Fatal编程技术网

Javascript Vuejs TypeError:无法读取属性';占位符';“未定义”的定义;

Javascript Vuejs TypeError:无法读取属性';占位符';“未定义”的定义;,javascript,vue.js,vuejs2,Javascript,Vue.js,Vuejs2,我有一个索引模板,它有两个子组件,post status和status preview 我正在向我的post statustemplateroutesuser和locale <post-status :user="user" :routes="routes" :locale="locale"> </post-status> 发布状态.vue <template> <div> <div cl

我有一个索引模板,它有两个子组件,
post status
status preview

我正在向我的
post status
template
routes
user
locale

<post-status
    :user="user"
    :routes="routes"
    :locale="locale">
</post-status>

发布状态.vue

<template>
    <div>
        <div class="bg-blue-lightest p-4">
            <form method="post" @submit.prevent="postStatus">
                <div class="flex">
                    <img :src="user.avatar" class="rounded-full w-8 h-8 items-end mr-3">
                    <textarea v-model="form.post" name="post" rows="5" class="w-full items-center rounded border-2 border-blue-lighter" :placeholder="locale.status.placeholder"></textarea>
                </div>
                <div class="ml-8 flex mt-4">
                    <div class="w-1/2 flex justify-start px-3">
                        <div class="mr-3">
                            <i class="text-blue-light fa fa-picture-o fa-2x"></i>
                        </div>
                        <div class="mr-3">
                            <i class="text-blue-light fa fa-bar-chart fa-2x"></i>
                        </div>
                        <div>
                            <i class="text-blue-light fa fa-map-pin fa-2x"></i>
                        </div>
                    </div>
                    <div class="w-1/2 flex justify-end">
                        <button class="bg-teal hover:bg-teal-dark text-white font-medium py-2 px-4 rounded-full">Tweet</button>
                    </div>
                </div>
            </form>
        </div>
    </div>
</template>

<script>
    export default {
        props: ['user', 'routes', 'locale'],
        data() {
            return {
                form: {
                    'post': '',
                },
            }
        },
        methods: {
            postStatus: function() {
                axios
                    .post(routes.store, this.form)
                    .then(response => {
                        console.log(response)
                    })
            },
        }
    }
</script>

<style scoped>

</style>

推特
导出默认值{
道具:['user','routes','locale'],
数据(){
返回{
表格:{
“post”:“,
},
}
},
方法:{
postStatus:function(){
axios
.post(routes.store,this.form)
。然后(响应=>{
console.log(响应)
})
},
}
}
这只是一个数据数组、表单路由、要翻译的区域设置以及包含一些用户信息的用户对象

否,当我呈现页面时,占位符工作正常:

但我收到了两条警告:

我的完整索引页:

<template>
    <div>
        <post-status
            :user="user"
            :routes="routes"
            :locale="locale">
        </post-status>

        <status-preview v-for="status in statuses"
            :key="status.id"
            :name="status.owner.name"
            :username="status.owner.username"
            :created="status.created_at"
            :post="status.post">
        </status-preview>
    </div>
</template>


<script>

    import StatusPreview from "./status-preview.vue";
    import PostStatus from "./post-status.vue";

    export default {
        components: {
            'status-preview': StatusPreview,
            'post-status': PostStatus
        },
        data() {
            return {
                routes: [],
                statuses: [],
                locale: [],
                user: [],
                completed : false,
                progress : false,
                page: 1
            }
        },
        methods: {
            getStatuses: function() {
                let url = this.routes.index + '?page=' + this.page
                axios
                    .get(url, {
                        page: this.page
                    })
                    .then(response => {
                        if (response.data.length) {
                            this.statuses = this.statuses.concat(response.data);
                            this.progress = false;
                        } else {
                            this.progress = false;
                            this.completed = true;
                        }
                        this.page += this.page;
                    });
            },
            infiniteScroll: function() {
                if (!this.completed &&  !this.progress) {
                    this.getStatuses()
                }

            },
        },
        mounted() {
            this.routes = routes
            this.locale = locale
            this.user = user
            this.getStatuses()
            window.addEventListener('scroll', this.infiniteScroll);
        }
    }
</script>

从“/status preview.vue”导入状态预览;
从“/post status.vue”导入PostStatus;
导出默认值{
组成部分:{
“状态预览”:状态预览,
“后状态”:后状态
},
数据(){
返回{
路线:[],
状态:[],
区域设置:[],
用户:[],
已完成:错误,
进展:错,
页码:1
}
},
方法:{
getStatuses:function(){
让url=this.routes.index+'?page='+this.page
axios
.get(url{
佩奇:这个。佩奇
})
。然后(响应=>{
if(响应.数据.长度){
this.statuses=this.statuses.concat(response.data);
这个。进步=错误;
}否则{
这个。进步=错误;
this.completed=true;
}
this.page+=this.page;
});
},
无限滚动:函数(){
如果(!this.completed&!this.progress){
这个文件名为getStatuses()
}
},
},
安装的(){
this.routes=routes
this.locale=locale
this.user=user
这个文件名为getStatuses()
window.addEventListener('scroll',this.infiniteScroll);
}
}
所有数据均设置为:

当它看起来工作正常时,是什么导致了此警告?

请查看:

装载的
阶段发生在第一次DOM渲染之后。在设置
区域设置之前,您正在等待它。这就是发生的情况:

- Your template is evaluated
- `this.locale` is still equal to your initial `[]`
- You get an error in your console saying `locale.status` is undefined
- The `mounted` event handler is executed, which populates your `locale` prop
- The component re-renders, since its props have changed
- `locale` is now set, your placeholder works

您可能应该使用
created
,而不是使用
mounted
,以确保在第一次渲染之前设置这些道具。

在这一行:
this.locale=locale
,右侧的
locale
变量来自哪里?我在任何地方都看不到它的定义。。。它是在其他文件中声明的全局变量吗?这是一种代码气味(与
路由
用户
相同)是的,它们是通过调用索引模板的html页面全局设置的。今天,我学习了。。。创建修复了该问题。。。将标记为最佳答案。谢谢,很好!有最好的记录之一。它写得很好,即使你不习惯阅读文档,也很容易理解。你肯定应该更深入地研究它:)