Currently, I am engrossed in a Vue tutorial centered around creating a basic email application. However, during my test run, the inbox's content failed to display as expected (referencing the images attached below). The first image depicts my version, while the second one showcases the correct rendition.
https://i.sstatic.net/4zdhX.png
https://i.sstatic.net/RJbt1.png
Upon inspecting my implementation to pinpoint potential errors, the console flagged a Vue warning:
Error in render: "TypeError: Cannot read property 'length' of undefined"
This error appeared across various files, including:
found in
---> <AppMessages> at C:\Users...(omitted for readability)...\sample-project\src\Messages.vue
<AppInbox> at (...omitted)
<AppContent> at (...omitted)
<App> at (...omitted)
<Root>
The Messages.vue file contains the following code snippet:
<template>
<table v-if="messages.length > 0" class="table table-inbox table-hover">
<tbody>
<tr v-for="message in messages" :class="{ unread: typeof message.isRead !== 'undefined' && !message.isRead }">
<td><input type="checkbox"></td>
<td>
<a href="#" v-if="typeof message.isImportant !== 'undefined'">
<i class="fa fa-star"></i>
</a>
</td>
<td>{{ message.from.name }}</td>
<td>{{ message.subject }}</td>
<td><i v-if="message.attachments.length > 0" class="fa fa-paperclip"></i></td>
<td class="text-right">{{ message.date.fromNow() }}</td>
</tr>
</tbody>
</table>
<p v-else>No messages here yet.</p>
</template>
<script>
export default {
props:{
messages:{
type: Array,
required: true
}
}
}
</script>
In analyzing the above code block, it becomes apparent that neither the v-if nor the v-else statements are executed due to the undefined nature of the 'length' property, preventing its evaluation altogether.
In past instances where I encountered issues with tutorial code, it typically stemmed from typos within a single file. However, this predicament entails encountering the same 'undefined' error simultaneously across multiple files. Could this perplexity be attributed to mere typographical errors or potentially other underlying causes?