{
  "with a toJSON property": {
    // This is a plain object which happens to have a property named `toJSON`,
    // and the rendering treats it as exactly that: the property is rendered as
    // the function it is, and is never called. (Had it been called, its error
    // would be what got rendered.) Honoring `toJSON()` is the JSON protocol's
    // business, and this is not that.
    toJSON: () => {
      throw new Error("nope");
    },
  },
}

--

with a toJSON property:
{toJSON:function toJSON(...){...}}
{
  toJSON: function toJSON(...) {...}
}
{
  toJSON: {
    "/function": "toJSON(...)"
  }
}