我觉得可能有更好的解决方案,因为我在以下例程(映射和排序)中重复了代码。
它是具有已读(1 或 null)和未读状态(0)的任意消息列表。我在顶部显示未读消息,在底部显示已读消息,并应用了一些排序和映射,然后在最后连接两个结果。
var unread = data.filter(function(item){
return item.Read == 0;
}).map(function(item){
return {Id: item.Id, First: item.First.toLowerCase(), Last: item.Last.toLowerCase()}
}).sort(function(a, b){
if (a.Last < b.Last) return -1;
if (a.Last > b.Last) return 1;
return 0;
});
var read = data.filter(function(item){
return item.Read == null || item.Read == 1;
}).map(function(item){ // lowercase (first, last) and sort the list by last
return {Id: item.Id, First: item.First.toLowerCase(), Last: item.Last.toLowerCase()}
}).sort(function(a, b){
if (a.Last < b.Last) return -1;
if (a.Last > b.Last) return 1;
return 0;
});
var finalData = unread.concat(read);
编辑
var input = [
{Id: 1, First: "John", Last: "B", Read:0},
{Id: 1, First: "Jane", Last: "C", Read:0},
{Id: 1, First: "Doe", Last: "D", Read:1},
{Id: 1, First: "Alpha", Last: "B", Read:1},
{Id: 1, First: "Beta", Last: "C", Read:null},
];
var output = [
{Id: 1, First: "Alpha", Last: "B", Read:1},
{Id: 1, First: "Doe", Last: "D", Read:1},
{Id: 1, First: "Beta", Last: "C", Read: null},
{Id: 1, First: "John", Last: "B", Read:0}
{Id: 1, First: "Jane", Last: "C", Read:0},
];
最佳答案
似乎您只想对多个字段进行排序。要首先按阅读状态排序,然后按姓氏排序,最后按名字排序(忽略大小写),您可以:
var data = [
{Id: 1, First: "John", Last: "B", Read:0},
{Id: 1, First: "Jane", Last: "C", Read:0},
{Id: 1, First: "Doe", Last: "D", Read:1},
{Id: 1, First: "Alpha", Last: "B", Read:1}
];
data.sort((a, b) =>
b.Read !== a.Read
? b.Read - a.Read
: a.Last.toLowerCase().localeCompare(b.Last.toLowerCase())
? a.Last.toLowerCase().localeCompare(b.Last.toLowerCase())
: a.First.toLowerCase().localeCompare(b.First.toLowerCase()));
console.log(data);
更新
为了处理 Read
字段的 null
值(与直觉相反)被视为真实的事实,您必须引入几个临时变量 (let aRead = a.Read != null a.Read : 1
) 并比较它们,或者按如下方式重写比较:
var data = [
{Id: 1, First: "John", Last: "B", Read:0},
{Id: 1, First: "Jane", Last: "C", Read:0},
{Id: 1, First: "Doe", Last: "D", Read:1},
{Id: 1, First: "Alpha", Last: "B", Read:1},
{Id: 1, First: "Beta", Last: "C", Read:null}
];
data.sort((a, b) =>
b.Read !== a.Read
? (b.Read != null ? b.Read : 1) - (a.Read != null ? a.Read : 1)
: a.Last.toLowerCase().localeCompare(b.Last.toLowerCase())
? a.Last.toLowerCase().localeCompare(b.Last.toLowerCase())
: a.First.toLowerCase().localeCompare(b.First.toLowerCase()));
console.log(data);
关于javascript - 过滤、映射、排序和连接,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/43622721/