使用变量过滤器对对象数组进行排序答案

【问题标题】：Sorting an array of objects with a variable filter使用变量过滤器对对象数组进行排序
【发布时间】：2020-04-15 20:58:32
【问题描述】：

我试图按当月过滤我的对象数组。以动物穿越鱼为例

const fishData = {
   "fish_name": "Barreleye",
   "price": "15,000",
   "location": "Sea",
   "shadow_size": "Small",
   "n_March": true,
   "n_3": true,

 },
 {
   "fish_name": "Coelacanth",
   "price": "15,000",
   "location": "Sea (Rainy Days)",
   "shadow_size": "Largest",
   "n_3": true,

 }
]

var today = new Date();
var currentMonth = today.getMonth();

var fishMonth = `n_ + ${currentMonth}`;
console.log(fishMonth);
var filteredFish = fishData.filter(function(i) {
    return i.fishMonth == true;
});

如果我输入 "n_3" 而不是 "fishMonth" 现在返回，代码运行良好。我检查了"fishMonth"，它确实返回了n_3。什么会阻止它工作？

【问题讨论】：

标签： javascript arrays filter javascript-objects

【解决方案1】：

你的fishMonth变量中有不必要的字符，应该是：

var fishMonth = `n_${currentMonth}`;

而且你还想读取对象的密钥，所以必须有return i[fishMonth] == true;，试试：

const fishData = [{
   "fish_name": "Barreleye",
   "price": "15,000",
   "location": "Sea",
   "shadow_size": "Small",
   "n_March": true,
   "n_3": true,

 },
 {
   "fish_name": "Coelacanth",
   "price": "15,000",
   "location": "Sea (Rainy Days)",
   "shadow_size": "Largest",
   "n_3": true,

 }
]

var today = new Date();
var currentMonth = today.getMonth();

var fishMonth = `n_${currentMonth}`;
var filteredFish = fishData.filter(function(i) {
    return i[fishMonth] == true;
});
console.log(filteredFish);

【讨论】：

【解决方案2】：

您需要不带空格的正确键值和+ 以及带括号的正确property accessor。

您可以进行更多更改，例如直接从实例中获取月份并直接返回所需属性的值。

const
    fishData = [{ fish_name: "Barreleye", price: "15,000", location: "Sea", shadow_size: "Small", n_March: true, n_3: true }, { fish_name: "Coelacanth", price: "15,000", location: "Sea (Rainy Days)", shadow_size: "Largest", n_3: true }],
    fishMonth = `n_${(new Date).getMonth()}`,
    filteredFish = fishData.filter(fish => fish[fishMonth]);

console.log(filteredFish);

最后，您可以更改整个数据结构并将月份作为值添加到对象中，并使用月份属性之类的东西。这允许使用与值的简单比较，而不是使用复合键。

const
    fishData = [{ fish_name: "Barreleye", price: "15,000", location: "Sea", shadow_size: "Small", n_March: true, month: 3 }, { fish_name: "Coelacanth", price: "15,000", location: "Sea (Rainy Days)", shadow_size: "Largest", month: 3 }],
    fishMonth = (new Date).getMonth(),
    filteredFish = fishData.filter(({ month }) => month === fishMonth);

console.log(filteredFish);

【讨论】：