title: Vue Keys do not delete from Object
body: <p>I'm trying to delete a key from an object in a parent component. A child component emits an event (with an item value) back to the parent method that triggers the delete in the parent's data object.</p>
  
  <p>Parent component: </p>
  
  <pre class="lang-js prettyprint-override"><code>data() {
    return {
      savedNews: Object
    }
  },
  methods: {
    containsKey(obj, key) {
      var result = Object.keys(obj).includes(key)
      return result
    },
    handleSaveNews(item) {
      if (!this.containsKey(this.savedNews, item.url)) {
        this.savedNews = {
          [item.url]: item,
          ...this.savedNews
        }
      } else {
        console.log(this.containsKey(this.savedNews, item.url))
        var res = delete(this.savedNews, item.url)
        console.log(res)
        console.log(this.containsKey(this.savedNews, item.url))
      }
    }
  }
  </code></pre>
  
  <p>All of the <code>console.log</code>s in the last else statement return true. It's saying that the delete was successful yet the key is still there. How do I delete this key?</p>