node.js - How to get loop variables in nodejs using for of to traverse Map

Question

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?

滿天的星座 · Answer

`for(value of map){

console.log(value[0]);

}`

学习ing · Answer

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 // 代表原来的索引
    }
}

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

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