Question

我想用三个值对这个JavaScript数组进行排序，但我似乎无法弄清楚如何一次按多个属性进行排序。

要求是：

featured项目应位于最顶端
然后使用否名称（null）
然后名称不 featured
按createdAt降序排列所有内容（最新的第一个）

这是数组：

var items [
    { name: 'foo-1', featured: true,  createdAt: 1493000001 },
    { name: null,    featured: false, createdAt: 1493000003 },
    { name: 'foo-3', featured: true,  createdAt: 1493000002 },
    { name: 'foo-4', featured: false, createdAt: 1493000004 },
    { name: 'foo-5', featured: false, createdAt: 1493000005 },
];

结果应为：

[
    { name: 'foo-3', featured: true,  createdAt: 1493000002 },
    { name: 'foo-1', featured: true,  createdAt: 1493000001 },
    { name: null,    featured: false, createdAt: 1493000003 },
    { name: 'foo-5', featured: false, createdAt: 1493000005 },
    { name: 'foo-4', featured: false, createdAt: 1493000004 },
]

Answer 1

var items = [
    { name: 'foo-1', featured: true,  createdAt: 1493000001 },
    { name: null,    featured: false, createdAt: 1493000003 },
    { name: 'foo-3', featured: true,  createdAt: 1493000002 },
    { name: 'foo-4', featured: false, createdAt: 1493000004 },
    { name: 'foo-5', featured: false, createdAt: 1493000005 },
];

items.sort(function(a, b) {
    if(a.featured && !b.featured) return -1; // if a is featured and b is not, then put a above b
    if(!a.featured && b.featured) return 1;  // if b is featured and a is not, then put b above a
    
    if(!a.name && b.name) return -1;         // if a doesn't have a name and b does, then put a above b
    if(a.name && !b.name) return 1;          // if b doesn't have a name and a does, then put b above a
    
    return b.createdAt - a.createdAt;        // otherwise (a and b have simillar properties), then sort by createdAt descendently
});

console.log(items);

Answer 2

您可以使用比较函数作为参数传递给sort（）函数 - 有关更多详细信息，请参阅Array.prototype.sort()。在您的情况下，比较功能可能如下所示：

var items = [
    { name: 'foo-1', featured: true,  createdAt: 1493000001 },
    { name: null,    featured: false, createdAt: 1493000003 },
    { name: 'foo-3', featured: true,  createdAt: 1493000002 },
    { name: 'foo-4', featured: false, createdAt: 1493000004 },
    { name: 'foo-5', featured: false, createdAt: 1493000005 },
];

function compare(a, b) {
    if (a.featured === true && b.featured === false) return -1;
    if (a.featured === false && b.featured === true) return 1;
    if (a.name === null && b.featured !== null) return -1;
    if (a.name !== null && b.name === null) return 1;

    return b.createdAt - a.createdAt;
};

items.sort(compare);

它应涵盖名称为空字符串的情况。

将JavaScript数组排序为3个值

2 个答案: