'How to evaluate Vue.js component props in the data property?

I have 2 components: Post and Comments.

Inside Post component, there is Comments component that has 3 props: postId, numCom (number of comments) and comments (array).

I get comments and I pass the array with props, and now I want to retrieve the array in Comments component and add it to data so I can then add/remove comments etc.

Here is my code in Comments.vue:

props: ['id', 'numCom', 'comments'],
data: function() {
  return {
     newMessage: "",
     loading: false,
     allComments: this.comments,
     num: this.numCom,
   }
},

But this doesn't works. In Vue developer tools I can see that comments prop is filled with comments, but allComments array is empty.

What should I do?

Solution 1:^[1]

It looks like the comments prop does not have a value at the time of the component's creation (which is the only time allComments will be set).

You can either:

Defer the creation of the component until the comments prop is ready by using v-if like this:

<comments v-if="comments" :comments="comments"></comments>

Watch for changes to the comments prop and set allComments to the new value (in addition to initializing allComments in the data function):

watch: {
  comments(value) {
    this.allComments = value;
  }
}

Solution 2:^[2]

Use computed properties

computed: {
  allComments () {
    return this.comments
  }
}

Solution 3:^[3]

You dont need to put the props into data, just use this[propName] to get the value.

If you want to change a prop value or key to another value,just use computed to change it.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1	Decade Moon
Solution 2	Florin Miu
Solution 3	radiorz

'How to evaluate Vue.js component props in the data property?

Solution 1:[1]

Solution 2:[2]

Solution 3:[3]

Sources

Related Questions

Solution 1:^[1]

Solution 2:^[2]

Solution 3:^[3]