My problem is to prevent duplicate data from being inserted when adding data to the array, so I thought of map, but I don’t know how to get the index after traversing the Map structure. If I don't use map, is there any other concise way?
2
0
0
1. The simplest
Every time you insert it, use the unique key to check whether it already exists
2. Use Object method when storing
let data = {
[id]: {
...obj,
index: Number // 代表原來的索引
}
}If you want to sort things in order when calling, use index to sort and then output.
Object.values(data).sort((a, b) => a.index - b.index);3. Create an index table while saving Array
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
