将嵌套对象虚拟体中的项拉入父对象数组

Question

我想使用这个对象数组，其中一些对象包含类似模式的数组，并创建一个新数组，其中它们都在同一级别。

[
{
"name": "United States",
"slug": "united-states",
"states":[
{
"name": "Arizona",
"slug": "arizona"
},
{
"name": "California",
"slug": "california"
}
]
},
{
"name": "Canada",
"slug": "canada",
}
]

这应该是最终结果：

[
{
"name": "United States",
"slug": "united-states"
},
{
"name": "Arizona",
"slug": "arizona"
},
{
"name": "California",
"slug": "california"
},
{
"name": "Canada",
"slug": "canada",
}
]

Answer 1

使用Array#flatMap:

const data = [
{
"name": "United States",
"slug": "united-states",
"states":[
{ "name": "Arizona", "slug": "arizona" },
{ "name": "California", "slug": "california" }
]
},
{ "name": "Canada", "slug": "canada" }
];
const res = data.flatMap(({ name, slug, states = [] }) => ([
{ name, slug },
...states
]));
console.log(res);

Answer 2

您可以创建一个遍历树的迭代器，然后将其消耗到数组中。这适用于更深层次的嵌套，并且不需要知道哪个属性具有子记录。它假设具有Array值的属性包含子树：

function * traverse(forest) {
for (const item of forest) {
const arrayKey = Object.entries(item).find(([k, v]) => Array.isArray(v))?.[0];
const { [arrayKey]: children, ...rest } = item;
yield rest;
if (children) yield * traverse(children);
}
}
const data = [{"name": "United States","slug": "united-states","states":[{ "name": "Arizona", "slug": "arizona" },{ "name": "California", "slug": "california" }]},{ "name": "Canada", "slug": "canada" }];
const res = [...traverse(data)];
console.log(res);