微信小程序开发的聚合函数排序.aggregate.sort

'use strict';
 const db = uniCloud.database() //对数据库的对象获取；
 
exports.main = async (event, context) => {
	let start = new Date().getTime();
	const collection = db.collection('usemall-visual') 
	const collection1 = db.collection('usemall-student') 

	let currentPage = event.currentPage;
	let pageSize = event.pageSize;

	 // 查找数据 寻找key为 更新出现的       
	let res = await collection.aggregate()
	.skip(currentPage) // 跳过前currentPage条
	.limit(pageSize) // 获取pageSize条
	.sort({
		ins_time:-1   //1:升序，2：降序
	})
	.lookup({
		from: "usemall-student",
		localField: "uid",
		foreignField: "_id",
		as: "stuinfo"
	})
	.project({ //关联别名
		'stuinfo._id': true,
		'stuinfo.name': true,
		'stuinfo.age': true,
		'stuinfo.scgc': true,
		'left_ver': true,
		'right_ver': true,
		'all_ver': true,
		'ins_time': true,
		'uid': true,
		quantity: true
	  })
	.end();
	
	let count = await collection.count();
	
	let response = {
		code: 1,
		order: []
	};
	
	response.data = res.data;
	response.count = count.total;
	response.name =  event.name;
	return response;

};