Toolbar doesn't allow objects

[yannick-mir]

I'm trying to change the label and tooltip of some of my toolbar items. I did it like in the documentation, but it's

data() {
    return {
      editorConfig: {
        removePlugins: ['Title'],
        toolbar: [
          'bold', 'italic', '|', 
          {
            label: 'YouTube/Spotify',
            tooltip: 'YouTube/Spotify Embed',
            items: [ 'mediaembed' ]
          },
          {
              label: 'Soundcloud',
              tooltip: 'Soundcloud Embed',
              items: [ 'htmlembed' ]
          },
        ]
      },
      contentHolder: ""
    }
  },

I'm getting ckeditorNuxt.common.js:194 toolbarview-item-unavailable