javascript - 以 dd/mm/yyyy 格式对 Javascript 中的日期进行排序

Question

函数排序日期有点问题。我想按 ASC 或 DESC 对所有日期进行排序，但排序不正确。

我的约会对象

let a = [
    "03/12/2019", "17/10/2020", "02/12/2019", "08/12/2019", "13/02/2020", 
    "23/03/2020", "18/11/2020", "29/02/2020", "05/12/2019", "03/06/2020",
    "06/05/2020", "09/09/2020", "28/10/2020", "07/04/2020", "27/04/2020",
    "28/05/2020", "29/12/2019", "31/10/2020", "23/09/2020", "25/12/2019",
    "14/01/2020", "30/09/2020", "18/05/2020", "14/06/2020", "25/04/2020",
    "19/08/2020", "26/03/2020", "19/05/2020", "15/03/2020", "11/10/2020",
    "25/04/2020", "16/12/2019", "14/08/2020", "19/08/2020", "28/02/2020",
    "01/01/2020", "07/06/2020", "17/11/2020", "22/05/2020", "31/07/2020",
    "20/01/2020", "07/02/2020", "18/08/2020", "16/02/2020", "13/03/2020",
    "21/12/2019", "02/03/2020", "24/07/2020", "01/05/2020", "31/01/2020",
    "25/11/2020", "07/07/2020", "16/07/2020", "06/07/2020", "16/09/2020",
    "29/07/2020", "19/06/2020", "09/08/2020", "25/08/2020", "21/02/2020",
    "30/11/2019", "04/06/2020", "06/09/2020", "10/09/2020", "26/11/2020",
    "22/07/2020", "21/05/2020", "25/07/2020", "05/01/2020", "17/06/2020",
    "14/07/2020"
];

函数排序

b.sort((d1, d2) => new Date(d1).getTime() - new Date(d2).getTime());

或替代

b.sort((b, a) => {
 if (b > a) {
   return 1;
 }
 if (b < a) {
   return -1;
 }
 return 0;
})

Answer 1

切勿使用 new Date(string) 构造函数或 Date.parse()解析日期字符串，因为这两种方法都不允许您提供特定格式或区域设置信息。 (Annoyingly, JavaScript's built-in Intl does not support parsing, only formatting)。

JavaScript 的 new Date(string) 和 Date.parse(string) 函数使用倾向于使用用户计算机的区域设置来解析日期 - 如果用户正在使用Windows 的 en-US 设置没有意识到 Date.parse(string) 和 new Date(string) 会将日期解释为 MM/dd/yyyy 而不是他们正确的区域设置。然而，浏览器往往会尝试解析你扔给它们的任何东西，如果它们看到 12/31/2019 或 31/12/2019 那么它们都会被解析为 2019-12-31 无论他们的计算机区域设置如何 - 只有当他们被赋予 5/7/2019 时，事情才会分崩离析，例如这将被解释为 2019-05-07 如果他们在美国或 2019-07-05 如果他们在英国。

不幸的是，您需要手动解析它们或使用像 Moment.JS 这样经过同行评审的库(因为编写日期库很难)。

let dates = [ "03/12/2019", "17/10/2020", "02/12/2019", ... ];

function parseDate( ddMMyyyy ) {

    const components = ddMMyyyy.split( '/' );
    if( components.length != 3 ) return null; 

    const dd   = parseInt( components[0] );
    const MM   = parseInt( components[1] );
    const yyyy = parseInt( components[2] );

    // Component range checking:
    if( dd >= 1 && dd <= 31 && MM >= 1 && MM <= 12 && yyyy >= 0 && yyyy <= 9999 ) {
        return new Date( yyyy, MM - 1, dd ); // `MM - 1` because JavaScript months are 0-based.
    } 
    else {
        return null;
    }
}

let sortedParsedDates = dates
    .map( parseDate )
    .filter( dt => dt instanceof Date )
    .sort( ( x, y ) => x.getTime() - y.getTime() );