如何在mongoose中更新文档后添加一些操作

Question

E.g。我有字段lastModified，当对象被修改时，该字段应该用当前日期更新。我怎么能用mongoose.js做这个呢？ 架构示例：

var schema = new Schema({
    someFieldForUpdates: {
        type: String,
    },
    //when 1st field changed this one should be updated too
    lastModified: {
        type: Date,
        default: Date.now()
    }
});

Answer 1

我认为可以使用后期保存或预先存储等中间件来完成 http://mongoosejs.com/docs/middleware.html

schema.post('save', function (doc) {
  console.log('%s has been saved', doc._id);
  // update another field 
})