[Javascript] bukld 'SQL' like object tree

最新推荐文章于 2025-09-04 18:55:33 发布

转载最新推荐文章于 2025-09-04 18:55:33 发布 · 92 阅读

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本文介绍了一种从多个数组中构建复杂树形数据结构的方法。通过映射、过滤和组合操作，将列表、视频、封面艺术和书签等元素整合成期望的数据格式。文章详细展示了如何使用JavaScript实现这一过程。

Let's try creating a deeper tree structure. This time we have 4 separate arrays each containing lists, videos, boxarts, and bookmarks respectively. Each object has a parent id, indicating its parent. We want to build an array of list objects, each with a name and a videos array. The videos array will contain the video's id, title, bookmark time, and smallest boxart url. In other words we want to build the following structure:

[
    {
        "name": "New Releases",
        "videos": [
            {
                "id": 65432445,
                "title": "The Chamber",
                "time": 32432,
                "boxart": "http://cdn-0.nflximg.com/images/2891/TheChamber130.jpg"
            },
            {
                "id": 675465,
                "title": "Fracture",
                "time": 3534543,
                "boxart": "http://cdn-0.nflximg.com/images/2891/Fracture120.jpg"
            }
        ]
    },
    {
        "name": "Thrillers",
        "videos": [
            {
                "id": 70111470,
                "title": "Die Hard",
                "time": 645243,
                "boxart": "http://cdn-0.nflximg.com/images/2891/DieHard150.jpg"
            },
            {
                "id": 654356453,
                "title": "Bad Boys",
                "time": 984934,
                "boxart": "http://cdn-0.nflximg.com/images/2891/BadBoys140.jpg"
            }
        ]
    }
]

Note: please make sure when creating objects (both lists and videos) that you add properties in the same order as above. This doesn't impact the correctness of your code, but the verifier expects properties to be created in this order.

function() {
    var lists = [
            {
                "id": 5434364,
                "name": "New Releases"
            },
            {
                "id": 65456475,
                name: "Thrillers"
            }
        ],
        videos = [
            {
                "listId": 5434364,
                "id": 65432445,
                "title": "The Chamber"
            },
            {
                "listId": 5434364,
                "id": 675465,
                "title": "Fracture"
            },
            {
                "listId": 65456475,
                "id": 70111470,
                "title": "Die Hard"
            },
            {
                "listId": 65456475,
                "id": 654356453,
                "title": "Bad Boys"
            }
        ],
        boxarts = [
            { videoId: 65432445, width: 130, height:200, url:"http://cdn-0.nflximg.com/images/2891/TheChamber130.jpg" },
            { videoId: 65432445, width: 200, height:200, url:"http://cdn-0.nflximg.com/images/2891/TheChamber200.jpg" },
            { videoId: 675465, width: 200, height:200, url:"http://cdn-0.nflximg.com/images/2891/Fracture200.jpg" },
            { videoId: 675465, width: 120, height:200, url:"http://cdn-0.nflximg.com/images/2891/Fracture120.jpg" },
            { videoId: 675465, width: 300, height:200, url:"http://cdn-0.nflximg.com/images/2891/Fracture300.jpg" },
            { videoId: 70111470, width: 150, height:200, url:"http://cdn-0.nflximg.com/images/2891/DieHard150.jpg" },
            { videoId: 70111470, width: 200, height:200, url:"http://cdn-0.nflximg.com/images/2891/DieHard200.jpg" },
            { videoId: 654356453, width: 200, height:200, url:"http://cdn-0.nflximg.com/images/2891/BadBoys200.jpg" },
            { videoId: 654356453, width: 140, height:200, url:"http://cdn-0.nflximg.com/images/2891/BadBoys140.jpg" }
        ],
        bookmarks = [
            { videoId: 65432445, time: 32432 },
            { videoId: 675465, time: 3534543 },
            { videoId: 70111470, time: 645243 },
            { videoId: 654356453, time: 984934 }
        ];

    return lists.map(function(list) {
        return {
            name: list.name,
            videos:
                videos.
                    filter(function(video) {
                        return video.listId === list.id;
                    }).
                    concatMap(function(video) {
                        return Array.zip(
                            bookmarks.filter(function(bookmark) {
                                return bookmark.videoId === video.id;
                            }),
                            boxarts.filter(function(boxart) {
                                return boxart.videoId === video.id;
                            }).
                            reduce(function(acc,curr) {
                                return acc.width * acc.height < curr.width * curr.height ? acc : curr;
                            }),
                            function(bookmark, boxart) {
                                return { id: video.id, title: video.title, time: bookmark.time, boxart: boxart.url };
                            });
                })
        };
    });

}