node.js 如何在每次保存时使用 Mongoose 架构中的当前日期更新属性？
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How do I update a property with the current date in a Mongoose schema on every save?
提问by wilsonpage
In my database collections, I want to update a 'lastChanged' field every time the record is updated with the current datetime. I want it to be in the same format as mongoose's default date like:
在我的数据库集合中，每次使用当前日期时间更新记录时，我都想更新“lastChanged”字段。我希望它与猫鼬的默认日期格式相同，例如：
ISODate("2011-10-06T14: 01: 31.106Z")
ISODate("2011-10-06T14: 01: 31.106Z")
Any words of wisdom?
有什么智慧的话吗？
回答by greenimpala
If you just want an ISO String use:
如果您只想要 ISO 字符串，请使用：
new Date().toISOString()
回答by Dave Jensen
One way of accomplishing this is to use Mongoose Middlewareand update the field pre-save.
实现此目的的一种方法是使用Mongoose Middleware并更新字段预保存。
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
//schema
var SomethingSchema = new Schema({
text: {type: String},
createdAt: {type: Date, default: Date.now},
updatedAt: {type: Date, default: Date.now}
});
//middle ware in serial
SomethingSchema.pre('save', function preSave(next){
var something = this;
something.updatedAt(Date.now());
next();
});
It seems, however, that the middleware is not always invoked:
然而，中间件似乎并不总是被调用：
Notes on findAndUpdate()
preandpostare not called for update operations executed directly on the database, includingModel.update,.findByIdAndUpdate,.findOneAndUpdate,.findOneAndRemove,and.findByIdAndRemove.order to utilizepreorpostmiddleware, you shouldfind()the document, and call theinit,validate,save, orremovefunctions on the document. See explanation.
findAndUpdate() 的注意事项
pre并且post不调用直接在数据库上执行的更新操作，包括Model.update,.findByIdAndUpdate,.findOneAndUpdate,.findOneAndRemove, 和.findByIdAndRemove.orderpre或post中间件，您应该find()使用文档，并调用文档上的init、validate、save、 或remove函数。见说明。
Update:See this question "add created_at and updated_at fields to mongoose schemas"
更新：请参阅此问题“将 created_at 和 updated_at 字段添加到猫鼬模式”
回答by Salvador Dali
In a few days Mongo is going to announce new 2.6 version (currently you can download experimental 2.5.x version). Among many other featuresyou can use $currentDatewhich is going to do exactly the thing you want:
几天后，Mongo 将发布新的 2.6 版本（目前您可以下载实验 2.5.x 版本）。在许多其他功能中，您可以使用$currentDate来完成您想要的事情：
db.users.update(
<criteria>,
{
$currentDate: { yourField: true},
}
)
