使用 es6 解构对象数组

Question

例如，我正在尝试将具有三个属性的对象数组解构为三个单独的数组

可能是这样的

const {wlAddresses,wlTokens,wlTickets} = Object.map()

或

const [wlAddresses,wlTokens,wlTickets] = Object.map()

Object.map() 返回类似这样的东西的地方

[{ wlAddresses: '23',
    wlTokens: 1,
    wlTickets: 3 },
  { wlAddresses: '24',
    wlTokens: 1,
    wlTickets: 2 },
  { wlAddresses: '25',
    wlTokens: 1,
    wlTickets: 3 }]

我尝试使用该方法，它只返回第一个对象，而不是后面的对象。我知道我可以通过映射对象并将所有内容作为单独的数组返回来解决这个问题，但也许我可以使用解构来做到这一点。

注意：这只是一个能不能做的问题，我不是强求答案

Answer 1

当您有一个对象或数组并且需要提取特定项目时，解构非常有用，但这里不是这种情况。您的数据不是一个简单的对象或数组——它是一个对象数组。您将无法通过简单的分配来做到这一点。您需要将数据转换为您想要的格式。例如这样的：

let arr = [{
    wlAddresses: '23',
    wlTokens: 1,
    wlTickets: 3
  },
  {
    wlAddresses: '24',
    wlTokens: 1,
    wlTickets: 2
  },
  {
    wlAddresses: '25',
    wlTokens: 1,
    wlTickets: 3
  }
]

let r = arr.reduce((acc, curr) => {
    for ([key, value] of Object.entries(curr)) {
        if (! acc[key]) acc[key] = []
        acc[key].push( curr[key])
    }
    return acc
}, {})


const {wlAddresses,wlTokens,wlTickets} = r

console.log(wlAddresses,wlTokens,wlTickets)

Answer 2

假设您的数组中的每个对象都将具有完全相同的相同的键，您可以只映射它。

const data = [{wlAddresses:'23',wlTokens:1,wlTickets:3},{wlAddresses:'24',wlTokens:1,wlTickets:2},{wlAddresses:'25',wlTokens:1,wlTickets:3}];
    
const r = Object.keys(data[0]).map((v) => ({ [v]: data.map((c) => c[v]) }));

console.log(JSON.stringify(r));

Answer 3

您可以使用嵌套循环和Object.entries()

let o = [{"wlAddresses":"23","wlTokens":1,"wlTickets":3},{"wlAddresses":"24","wlTokens":1,"wlTickets":2},{"wlAddresses":"25","wlTokens":1,"wlTickets":3}];

let entries = Object.entries(o);
    let res = Array.from({length:entries.length}).fill([]);
    for (let [, {wlAddresses,wlTokens,wlTickets}] of entries) {   
      Object.entries({wlAddresses,wlTokens,wlTickets})
      .forEach(([, prop], index) => {
        res[index] = [...res[index], prop]
      })
    }
    
let [wlAddresses,wlTokens,wlTickets] = res;

console.log(wlAddresses,wlTokens,wlTickets);

单独使用解构赋值

let o = [{"wlAddresses":"23","wlTokens":1,"wlTickets":3},{"wlAddresses":"24","wlTokens":1,"wlTickets":2},{"wlAddresses":"25","wlTokens":1,"wlTickets":3}];

let len = o.length;

let [wlAddresses,wlTokens,wlTickets] = Array.from({length:len}, () => []);

let i = 0;

if (i < len) {
  ({wlAddresses:wlAddresses[wlAddresses.length]
  , wlTokens:wlTokens[wlTokens.length]
  , wlTickets:wlTickets[wlTickets.length]} = o[i]);
  console.log(wlAddresses,wlTokens,wlTickets);
  ++i;
} else {
  console.log("done");
  console.log(wlAddresses,wlTokens,wlTickets);
}

if (i < len) {
  ({wlAddresses:wlAddresses[wlAddresses.length]
  , wlTokens:wlTokens[wlTokens.length]
  , wlTickets:wlTickets[wlTickets.length]} = o[i]);
  console.log(wlAddresses,wlTokens,wlTickets);
  ++i;
} else {
  console.log("done");
  console.log(wlAddresses,wlTokens,wlTickets);
}

if (i < len) {
  ({wlAddresses:wlAddresses[wlAddresses.length]
  , wlTokens:wlTokens[wlTokens.length]
  , wlTickets:wlTickets[wlTickets.length]} = o[i]);
  console.log(wlAddresses,wlTokens,wlTickets);
  ++i;
} else {
  console.log("done");
  console.log(wlAddresses,wlTokens,wlTickets);
}

if (i < len) {
  ({wlAddresses:wlAddresses[wlAddresses.length]
  , wlTokens:wlTokens[wlTokens.length]
  , wlTickets:wlTickets[wlTickets.length]} = o[i]);
  console.log(wlAddresses,wlTokens,wlTickets);
  ++i;
} else {
  console.log("done");
  console.log(wlAddresses,wlTokens,wlTickets);
}

在第二个硬编码的 sn-p 处使用带有代码的循环

let o = [{"wlAddresses":"23","wlTokens":1,"wlTickets":3},{"wlAddresses":"24","wlTokens":1,"wlTickets":2},{"wlAddresses":"25","wlTokens":1,"wlTickets":3}];

let len = o.length;

let [wlAddresses,wlTokens,wlTickets] = [[], [], []];

let i = 0;

while (i < len) {
  ({wlAddresses:wlAddresses[wlAddresses.length]
  , wlTokens:wlTokens[wlTokens.length]
  , wlTickets:wlTickets[wlTickets.length]} = o[i]);
  ++i;
}
  
console.log("done");
console.log(wlAddresses,wlTokens,wlTickets);