javascript 如何在javascript Map中保持序列？
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How to keep the sequence in javascript Map?
提问by emilly
i have myData map as below
我有如下 myData 地图
var myData = new Object();
myData[10427] = "Description 10427";
myData[10504] = "Description 10504";
myData[10419] = "Description 10419";
but now when i iterate over myData, i don't get same sequnce in chrome and IE works fine in firefox. It iterates in ascending order of key
但是现在当我遍历 myData 时，我在 chrome 中没有得到相同的序列，而 IE 在 Firefox 中工作正常。它以键的升序迭代
for (var key in myData) {
alert("key is"+key);
}
i get the output in ascending order in alert as 10419,10427,10504
我在警报中按升序得到输出 10419,10427,10504
How i can make sure to iterate in same order as data as inserted in map?
我如何确保以与插入到地图中的数据相同的顺序进行迭代？
回答by Mamtha Soni K
ES6 Maps preserves the insertion order.
ES6 Maps 保留插入顺序。
The set method is used for setting the key value pairs
set方法用于设置键值对
var myData = new Map();
myData.set(10427, "Description 10427");
myData.set(10504, "Description 10504");
myData.set(10419, "Description 10419");
Map keys and values are printed using
使用映射键和值打印
myData.forEach((value,key) => console.log(key, value));
This will print the keys and values in the insertion order
这将打印插入顺序中的键和值
回答by Quentin
Objects are unordered in JS. Use an array if order matters.
JS 中的对象是无序的。如果顺序很重要，请使用数组。
var myData = [];
myData.push({ "number": 10427, description: "Description 10427" });
