Vue devtools CustomValue API

backend.js

const sendThisToDevtools = {
  _custom: {
    type: 'set',
    display: 'Set[3]',
    readOnly: true,
    value: [1, 2, {
      _custom: {
        type: 'map',
        display: 'Map[3]',
        value: { a: 42, b: 'foo' }
      }
    }]
  }
}