Javascript 学习笔记《对象与数组转换》

左手的ㄟ右手 2022-12-27 04:53 174阅读 0赞

### Javascript 学习笔记 Map 和 Array 转换 ###

*  对象 2 数组
 *   *  取 key 数组
     *  取 value 数组
     *  格式化后输出
 *  数组 2 对象
 *  Array 2 Tree

# 对象 2 数组 #

## 取 key 数组 ##

Object.keys(obj);

## 取 value 数组 ##

Object.values(obj);

## 格式化后输出 ##

对象：`{"a":1,"b":2,"c":3}`  
数组：`[{"name":"a","value":1}, {"name":"b","value":2}, {"name":"c","value":3}]`

var obj = { "a":1, "b":2,"c":3}
    var arr = Object.keys(obj).map((k) => ({ 'name': k, 'value': obj[k]}) );
    console.info(arr);

输出

[
        {  "name": "a", "value": 1 },
        {  "name": "b", "value": 2 },
        {  "name": "c", "value": 3 }
    ]

# 数组 2 对象 #

数组：`[{"name":"a","value":1}, {"name":"b","value":2}, {"name":"c","value":3}]`  
对象：`{"a":1,"b":2,"c":3}`

var arr = [{ "name":"a","value":1}, { "name":"b","value":2}, { "name":"c","value":3}];
    var obj = { };
    arr.forEach(v => obj[v.name] = v.value);
    console.info(obj);

var arr = [{ "name":"a","value":1}, { "name":"b","value":2}, { "name":"c","value":3}];
    var obj = arr.reduce((acc, cur) => { acc[cur.name] = cur.value; return acc;}, { });
    console.info(obj);

如果对象内每个元素都是数组

# Array 2 Tree #