如何检查文档是否真的更新了

Imagine the following model:

想象以下模型:

var Office = 
{
    id: 1,
    name: "My Office",
    branches: 
    [
      {
        adddress: "Some street, that avenue",
        isPrincipal: true,
      },
      {
        adddress: "Another address",
        isPrincipal: false,
      },      
    ]
}
var Of