js获取一年中所有的周数和对应的日期_dayjs获取每年的自然周

js获取一年中所有的周对应的日期
调用: setweekOption(‘2020’)

//设置周下拉框
export function setweekOption(year) { //传入年份,字符串类型年份,'2020'
    year = new Date(year).getFullYear()
    let days = getDay(year || new Date().getFullYear())
    // console.log(days)
    let weeks = {};
    for (let i = 0; i < days.length; i++) {
        let weeksKeyLen = Object.keys(weeks).length;
        let daySplit = days[i].split('_');
        if (weeks[weeksKeyLen] === undefined) {
            weeks[weeksKeyLen + 1] = [daySplit[0]]
        } else {
            if (daySplit[1] == '1') {
                weeks[weeksKeyLen + 1] = [daySplit[0]]
            } else {
                weeks[weeksKeyLen].push(daySplit[0])
            }
        }
    }
    let option = []
    let weeksKeyLen = Object.keys(weeks).length;
    for (let i = 1; i < weeksKeyLen + 1; i++) {
        let obj = {};
        obj.year = year
        obj.week = "第" + i + "周" 
        obj.md = weeks[i][0] + '-' + weeks[i][weeks[i].length - 1] 
        obj.s = weeks[i][0]
        obj.e = weeks[i][weeks[i].length - 1] 

        obj.text = "第" + i + "周" + '(' + weeks[i][0] + '-' + weeks[i][weeks[i].length - 1] + ')';
        obj.value = i;
        option.push(obj)

    }
    return option;
}
export function getDay(year) {
    let dates = [];
    for (let i = 1; i <= 12; i++) {
        for (let j = 1; j <= new Date(year, i, 0).getDate(); j++) {
            dates.push(formatNumber(i) + '/' + formatNumber(j) + '_' + new Date([year, formatNumber(i), formatNumber(j)].join('-')).getDay()) //返回当年所有日期（带星期数）
        }
    }
    return dates;
}
export function formatNumber(n) {
    return n.toString().length > 1 ? n : '0' + n
}
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