JS：将数组减少为嵌套对象
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所以我有这个阵列
var mapped = [[2016, "October", "Monday", {object}], [2017, "January", "Friday", {object}], [2017, "January", "Wednesday", {object}], [2017, "October", "Monday", {object}]]
我想要完成的是这样的事情：
[{
"2016": [{
"October": [{
"Monday": [{object}]
}]
}],
}, {
"2017": [{
"January": [{
"Friday": [{object}]
}, {
"Wednesday": [{object}]
}]
}, {
"October": [{
"Monday": [{object}]
}]
}]
}]
我一直在寻找这么久，我找不到解决方案..通过使用reduce，我得到这样的东西：
[
2016: [{
"month": "October"
}]
],
[
2017: [{
"month": "January"
},
{
"month": "January"
},
{
"month": "September"
}]
]
所以看起来我已经融入了某些东西，但仍然遥远......这就是我正在做的事情：
mapped.reduce((years, array) => {
years[array[0]] = years[array[0]] || [];
years[array[0]].push({
month: array[1]
})
return years;
}, [])
答案
不完全是你指定的，但我觉得以下脚本输出的格式最有用 - 它只生成最深层次的数组：
const mapped = [[2016, "October", "Monday", { a: 1 }], [2017, "January", "Friday", { a: 1 }], [2017, "January", "Wednesday", { a: 1 }], [2017, "October", "Monday", { a: 1 }]];
const result = mapped.reduce( (acc, [year, month, day, object]) => {
let curr = acc[year] = acc[year] || {};
curr = curr[month] = curr[month] || {};
curr = curr[day] = curr[day] || [];
curr.push(object);
return acc;
}, {});
console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }另一答案
要获得完全相同的结构，您可以尝试以下策略。这将适用于任何级别的嵌套，并将继续构建嵌套对象。请查看示例，以查看将进行一般处理的各种嵌套级别。
- 将每个元素映射到相应的嵌套结构（使用reduce映射）
- 将映射数组中的每个元素组合到一个对象中以合并所有冗余键
- 将最终的嵌套对象转换为所需的数组结构。
const mapped = [[2016, "October", "Monday", "Morning", {time: "10AM"}], [2017, "January", "Friday", {object: "OBJECT"}], [2017, "January", "Wednesday", {object: "OBJECT"}], [2017, "October", "Monday", {object: "OBJECT"}]];
// Map all objects to the respective nested structure
const nestedMap = mapped.map(elem => {
let reversed = [...elem.reverse()];
let firstElem = reversed.splice(0, 1)[0];
return reversed.reduce((acc, elem) => {let newAcc = {}; newAcc[elem] = [acc]; return {...newAcc}}, firstElem);
})
// Combine array to form a single object
const nestedObj = nestedMap.reduce((acc, elem) => {
let firstKey = Object.keys(elem)[0];
acc[firstKey]
?
acc[firstKey].push(elem[firstKey][0])
:
acc[firstKey] = elem[firstKey];
return acc;
}, {})
// Convert back into the array with each object as element
const nestedFinalArr = Object.keys(nestedObj).map(key => ({[key]: nestedObj[key]}))
console.log(nestedFinalArr);以上是关于JS：将数组减少为嵌套对象的主要内容，如果未能解决你的问题，请参考以下文章