如何獲得在JavaScript中輸入日期的星期數？

Question

我正在嘗試獲取當前日期/特定日期的週數。任何關於邏輯構建的建議都將有所幫助。

Answer 1

function getWeekNumber(thisDate) { 
var dt = new Date(thisDate); 
var thisDay = dt.getDate(); 

var newDate = dt; 
newDate.setDate(1); // first day of month 
var digit = newDate.getDay(); 

var Q = (thisDay + digit)/7; 

var R = (thisDay + digit) % 7; 

if (R !== 0) return Math.ceil(Q); 
else return Q;} 

getWeekNumber（「07/31/2016」）;

Answer 2

let _ = new Date, 
    __ = ~~((new Date(_.getFullYear(), 0, 0) - _)/36e5 * 24), 
    ___ = (__ - __ % 7)/7;