（学习的本质，不在于记住哪些知识，而在于它触发了你的思考——迈克尔·桑德尔）
假如有以下数据结构
其中features内value的数据结构是可变的
{
"_id": {
"$oid": "64bd0b17258d09faf6ebb6ee"
},
"id": {
"id": "dania.mndz",
"platform": "INSTAGRAM"
},
"__v": 0,
"createdAt": {
"$date": "2022-08-05T06:42:18.673Z"
},
"features": [
{
"type": "SHARED_NICKNAME_AVATAR",
"value": {
"nickname": "Dania Mendez",
"avatar": "https://cdn.hypeauditor.com/img/instagram/user/15148153672.jpg?w=320&till=1697914801&sign=96da71c49c59693daf2e033bcf70dba3"
}
}
],
"updatedAt": {
"$date": "2023-07-22T19:00:00.554Z"
}
}
对应的管道函数操作
[
{
$match: {
// 筛选日期
createdAt: {
$lte: new Date(1690127999999),
},
// 多个同时满足的条件
$and: [
{
"features.type": "SHARED_EMAIL",
},
// value字段必须存在
{
"features.value": {
$exists: true,
},
},
// value字段不能为空字符串
{
"features.value": {
$ne: "",
},
},
// value字段不能为以下模糊值
{
"features.value": {
$nin: [
/gmail.com/,
/outlook.com/,
/yahoo.com/,
/icloud.com/,
/mail.qq.com/,
/qq.com/,
/mail.ru/,
/aol.com/,
/gmx.com/,
/mail.com/,
/mail.163.com/,
/163.com/,
/protonmail.com/,
/zoho.com/,
/yandex.com/,
/mail.sohu.com/,
/sohu.com/,
/hotmail.com/,
/126.com/,
/hushmail.com/,
/tutanota.com/,
/mail.sina.com.cn/,
/sina.com.cn/,
/naver.com/,
/fastmail.com/,
/posteo.de/,
],
},
},
],
},
},
{
// 排序
$sort: {
createdAt: -1,
},
},
{
$project: {
name: "$id.id",
platform: "$id.platform",
// 对features进行过滤，只获取type等于SHARED_COUNTRY的
countries: {
$filter: {
input: "$features",
as: "doc",
cond: {
$eq: ["$$doc.type", "SHARED_COUNTRY"],
},
},
},
emails: {
$filter: {
input: "$features",
as: "doc",
cond: {
$eq: ["$$doc.type", "SHARED_EMAIL"],
},
},
},
flowwers: {
$filter: {
input: "$features",
as: "doc",
cond: {
$eq: [
"$$doc.type",
"SHARED_FOLLOWER_COUNT",
],
},
},
},
categories: {
$filter: {
input: "$features",
as: "doc",
cond: {
$eq: [
"$$doc.type",
"SHARED_CATEGORY",
],
},
},
},
_id: 0,
},
},
{
$project: {
name: 1,
// 对emails进行截取，获取数组内的第一个
email: {
$first: "$emails.value",
},
fansCount: {
$first: "$flowwers.value",
},
platform: 1,
// 将platform值放入数组中
platforms: ["$platform"],
countries: [
{
$first: "$countries.value",
},
],
categories: {
$first: "$categories.value",
},
media: {
// 使用条件分支
$switch: {
branches: [
{
// 如果platform的值等于INSTAGRAM
case: {
$eq: ["$platform", "INSTAGRAM"],
},
// 则使用$concat操作符将一下三个字符串进行拼接，其中$name是变量值
then: {
$concat: [
"https://www.instagram.com/",
"$name",
"/",
],
},
},
{
case: {
$eq: ["$platform", "YOUTUBE"],
},
then: {
$concat: [
"https://www.youtube.com/channel/",
"$name",
"/",
],
},
},
{
case: {
$eq: ["$platform", "TIKTOK"],
},
then: {
$concat: [
"https://www.tiktok.com/@",
"$name",
"/",
],
},
},
],
// 否则返回默认值
default: "Did not match",
},
},
},
},
{
$project: {
platform: 0,
},
},
]
返回示例
{
"name": "___2toua2___",
"email": "[email protected]",
"fansCount": 620204,
"platforms": [
"INSTAGRAM"
],
"countries": [
"JP"
],
"categories": [
"1041",
"1017"
],
"media": "https://www.instagram.com/___2toua2___/"
}