在javascript中使用map或reduce将二维数组转换为对象

是否可以转换

[[35, "Bill"], [20, "Nancy"], [27, "Joan"]]

to

{"Bill": 35, "Nancy": 20, "Joan": 27}

使用.map() or .reduce()方法？

我可以使用以下方法转换数组：

const arr = [[35, "Bill"], [20, "Nancy"], [27, "Joan"]];

let obj = {};

for (let item of arr) {
  obj[item[1]] = item[0];
}

console.log(obj);

但我尝试使用map or reduce正在失败。有任何想法吗？

如果支持，您可以使用Object.fromEntries() https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/fromEntries转换数组[key, value]与一个对象配对。在这种情况下，这些对是[value, key]，所以我们需要首先将它们映射到一个数组[key, value] pairs.

const arr = [[35, "Bill"], [20, "Nancy"], [27, "Joan"]];

const obj = Object.fromEntries(arr.map(([v, k]) => [k, v]));

console.log(obj);

Use Array.map() https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map创建一个对象数组，其中每个对象包含一个键/值。将它们组合成一个对象传播 https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax into Object.assign() https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign:

const arr = [[35, "Bill"], [20, "Nancy"], [27, "Joan"]];

const obj = Object.assign(...arr.map(([v, k]) => ({ [k]: v })));

console.log(obj);

如果您需要将对象用作字典，更好的解决方案是将元组数组转换为Map https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map:

const arr = [[35, "Bill"], [20, "Nancy"], [27, "Joan"]];

const map = new Map(arr.map(([v, k]) => [k, v]));

console.log(map.get('Bill'));