本节目的：从数据库获取对应文章的评论加载到页面

1. 实现加载评论样式效果

 2. 创建获取评论云函数 get_comments，并配置运行测试参数

'use strict'; const db = uniCloud.database() const $ = db.command.aggregate exports.main = async (event, context) => {     const {         user_id,         article_id,     } = event
    const list = await db.collection('article')         .aggregate()         .match({             _id: article_id         })         // 拆分数组中的每个文档为多个         .unwind('$comments')         .project({             _id: 0,             // 只返回 comments             comments: 1         })         // 指定字段作为根节点         .replaceRoot({             newRoot: '$comments'         })         .end()     //返回数据给客户端     return {         code: 200,         msg: '数据请求成功',         data: list.data     } };
// data[0] 是一个对象，把对象替换掉，内容为原对象value值（数组)里的每一项
// 未拆分之前返回结果 // { //  "code": 200, //  "data": [{ //      "comments": [{ //          "author": { //              "author_id": "5f45afe33c788800019dfb0b", //              "author_name": "Java架构师讲师团", //              "avatar": "//img2.sycdn.imooc.com/5dafce1a00013fd501400140-160-160.jpg", //              "professional": "架构师" //          }, //          "comment_content": "评论2", //          "comment_id": "4y4z5caxzwk0", //          "create_time": 1599608617064, //          "replys": [] //      }, { //          "author": { //              "author_id": "5f45afe33c788800019dfb0b", //              "author_name": "Java架构师讲师团", //              "avatar": "//img2.sycdn.imooc.com/5dafce1a00013fd501400140-160-160.jpg", //              "professional": "架构师" //          }, //          "comment_content": "评论1", //          "comment_id": "1uv9hscv45kw", //          "create_time": 1599608595513, //          "replys": [] //      }, { //          "author": { //              "author_id": "5f45afe33c788800019dfb0b", //              "author_name": "Java架构师讲师团", //              "avatar": "//img2.sycdn.imooc.com/5dafce1a00013fd501400140-160-160.jpg", //              "professional": "架构师" //          }, //          "comment_content": "评论成功", //          "comment_id": "5156s0kekqk0", //          "create_time": 1599524585856, //          "replys": [] //      }] //  }], //  "msg": "数据请求成功" // }
// 拆分之后 // { //  "code": 200, //  "msg": "数据请求成功", //  "data": [{ //      "comment_id": "4y4z5caxzwk0", //      "comment_content": "评论2", //      "create_time": 1599608617064, //      "author": { //          "author_id": "5f45afe33c788800019dfb0b", //          "author_name": "Java架构师讲师团", //          "avatar": "//img2.sycdn.imooc.com/5dafce1a00013fd501400140-160-160.jpg", //          "professional": "架构师" //      }, //      "replys": [] //  }, { //      "comment_id": "1uv9hscv45kw", //      "comment_content": "评论1", //      "create_time": 1599608595513, //      "author": { //          "author_id": "5f45afe33c788800019dfb0b", //          "author_name": "Java架构师讲师团", //          "avatar": "//img2.sycdn.imooc.com/5dafce1a00013fd501400140-160-160.jpg", //          "professional": "架构师" //      }, //      "replys": [] //  }, { //      "comment_id": "5156s0kekqk0", //      "comment_content": "评论成功", //      "create_time": 1599524585856, //      "author": { //          "author_id": "5f45afe33c788800019dfb0b", //          "author_name": "Java架构师讲师团", //          "avatar": "//img2.sycdn.imooc.com/5dafce1a00013fd501400140-160-160.jpg", //          "professional": "架构师" //      }, //      "replys": [] //  }] // }

测试参数：

{
"user_id": "5f45afe33c788800019dfb0b",
"article_id": "5f45afe0875241000188959f"
}

3. 页面加载

3.1 获取

 3.2 渲染及传值给组件

 3. 子组件渲染