Vue, v-bind: Passing data as a property

Question

I am trying to pass data as a property in a component. v-bind is required, but i can't seem to make it work. Error is one line 3 in the HTML, the v-bind directive doesn't work and returns an error: "Custom elements in iteration require a "v-bind:key" directive"

 <script> export default { name: "ChatLog", props: { }, components: {ChatMessage}, data() { return { messages: [ { message: "Hey", user: "James" }, { message: "Hola", user: "Jimmy" }, ] } } } </script>

 <template> <div class="log"> <ChatMessage v-for="(message) in messages" v-bind:message="message"> </ChatMessage> </div> </template>

Answer 1

You may try this (The key is required in a loop):

<template>
    <div class="log">
       <ChatMessage
           v-for="(message, key) in messages"
           v-bind:message="message"
           v-bind:key="key"
       ></ChatMessage>
    </div>
</template>

Btw, you may use shorthand alternative for v-bind like this:

<ChatMessage v-for="(message, key) in messages" :message="message" :key="key" />

Also, if message is unique, then you may use the message as the value for key like this:

<ChatMessage v-for="message in messages" :message="message" :key="message" />

Note: Read more about the key here.

Answer 2

您需要在 for 循环中为给定元素指定一个键。

<ChatMessage v-for="(message) in messages" v-bind:message="message" :key="message"> </ChatMessage>