When using the v-for directive with an array passed as props, an error is

I encountered an issue while passing an array of objects from parent to child and looping over it using v-for. The error message "TypeError: Cannot read property 'title' of undefined" keeps appearing.

My parent component is named postsList, while the child component is named Post.

If you'd like to check out the code on codesandbox, here's the link: https://codesandbox.io/s/vue-template-hh0hi

Any ideas on how to resolve this problem?


// Parent 
<template>
  <div class="hello">
    <Post :posts="posts"/>
  </div>
</template>

<script>
import Post from './Post'

export default {
  name: "PostsList",
  data: () => {
    return {
      posts: [
        { title: 'one', description: 'desc one'},
        { title: 'two', description: 'desc two'}
      ]
    }
  },
  components: {
    Post
  },
  props: {
    msg: String
  }
};
</script>


Child

<template>
  <div :v-for="post in posts" class="hello">
    {{post.title}}
  </div>
</template>

<script>
export default {
  name: "Post",
 props: {
    title: { type: String, default: 'asdff' },
    posts: {
      type: Array,
      default: () => []
    }
  }
};
</script>

Answer №1

Make sure to enclose your Post component within a single div element, as shown below:

<template>
   <div>
      <div v-for="post in posts" class="hello">
         {{post.title}}
      </div>
   </div>
</template>

Remember that a Vue template should have only one root element.

Also, avoid using : before v-for as it will cause an error.

Check out this working example for reference.

Answer №2

When working with v-for, it's important to remember that you don't need to include the colon before the variable. Adding the colon can cause Vue to try and interpret the expression as if it were a component property, which can result in error messages about the variable not being registered reactively.

Additionally, if you encounter error messages related to using v-for on the root element of a component, pay attention to them. It's necessary to wrap the elements within another container or a <template> tag, as each component should have only one root element.

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