如何从Javascript中的日期编号获取星期几？

Question

给出分别dayNumber来自0..6代表Monday..Sunday.

可以使用Date/ String对象来获取星期几dayNumber吗？

Answer 1

一种更优雅的方式,允许您按区域设置显示工作日,如果您选择启动最新版本的ECMA脚本并且在所有最新浏览器和node.js中运行:

console.log(new Date().toLocaleString('en-us', {  weekday: 'long' }));

Answer 2

这将根据您传递的索引给您一天:

var weekday=new Array(7);
weekday[0]="Monday";
weekday[1]="Tuesday";
weekday[2]="Wednesday";
weekday[3]="Thursday";
weekday[4]="Friday";
weekday[5]="Saturday";
weekday[6]="Sunday";
console.log("Today is " + weekday[3]);

输出"今天是星期四"

您可以使用JavaScript获取当前天数索引getDay()(但在此方法中,星期日为0,星期一为1,等等):

var d=new Date();
console.log(d.getDay());

星期一输出1.

Answer 3

此代码是上面给出的修改版本.它返回表示日期的字符串

/**
* Converts a day number to a string.
*
* @param {Number} dayIndex
* @return {String} Returns day as string
*/
function dayOfWeekAsString(dayIndex) {
  return ["Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday"][dayIndex];
}

例如

dayOfWeekAsString(0) returns "Monday"

Answer 4

/**
* I convert a day string to an number.
*
* @method dayOfWeekAsInteger
* @param {String} day
* @return {Number} Returns day as number
*/
function dayOfWeekAsInteger(day) {
  return ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"].indexOf(day);
}

Answer 5

这将添加一个getDayOfWeek()函数作为JavaScript Date类的原型.

Date.prototype.getDayOfWeek = function(){   
    return ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"][ this.getDay() ];
};