[Vuejs]-Vue warning when accessing nested object

13👍

Totally guessing here but lets see if I’m right…

Say you’ve got something like this in your component / Vue instance data initialiser…

data () {
  return {
    user: {}
  }
}

and you then populate that object asynchronously, eg

mounted () {
  setTimeout(() => { // setTimeout is just an example
    this.user = {
      ...this.user,
      area: {
        name: 'foo'
      }
    }
  }, 1000)
}

If your template has

{{ user.area.name }}

when it initially renders before the asynchronous task has completed, you will be attempting to access the name property of area which is undefined.

Example ~ http://jsfiddle.net/tL1xbmoj/


Your options are…

  1. Initialise your data with a structure that won’t cause errors

    data () {
      return {
        user: {
          area: { 
            name: null 
          } 
        }
      }
    }
    

    Example ~ http://jsfiddle.net/tL1xbmoj/1/

  2. Use conditional rendering to prevent the error

    <span v-if="user.area">{{ user.area.name }}</span>
    

    Example ~ http://jsfiddle.net/tL1xbmoj/2/

👤Phil

0👍

Your user doesn’t contain an area, so when you try to read that, it’s undefined. You’re not allowed to use the . operator on things that are undefined, so when you do .name on that, you get the error that you got.

0👍

You could also use a ternary operator {{ user.area ? user.area.name : "" }}

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