题解 | #时间格式化输出#

function formatDate(date, fmt){
    let dateObj = new Date(date)
    let year = dateObj.getFullYear()
    let month = dateObj.getMonth() + 1
    let dat = dateObj.getDate()
    let hours = dateObj.getHours()
    let minutes = dateObj.getMinutes()
    let sec = dateObj.getSeconds()
    let day = dateObj.getDay()

    fmt = fmt.replace(/(y+)/g,function(match,p1){

        return String(year).replace(new RegExp(`^\\d{${4-p1.length}}`,'g'),'')
    })

    fmt = fmt.replace(/(M+)/g,function(match,p1){
        return p1.length > 1 && month < 10 ? '0' + month : month
    })

    fmt = fmt.replace(/(d+)/g,function(match,p1){
        return p1.length > 1 && dat < 10 ? '0' + dat : dat
    })

    fmt = fmt.replace(/(H+)/g,function(match,p1){
        return p1.length > 1 && hours < 10 ? '0' + hours : hours
    })

    fmt = fmt.replace(/(h+)/g,function(match,p1){
       if(hours > 12){
           hours-= 12
       }
       return p1.length > 1 && hours < 10 ? '0' + hours : hours
    })

    fmt = fmt.replace(/(m+)/g,function(match,p1){
       return p1.length > 1 && minutes < 10 ? '0' + minutes : minutes
    })

    fmt = fmt.replace(/(s+)/g,function(match,p1){
       return p1.length > 1 && sec < 10 ? '0' + sec : sec
    })

    fmt = fmt.replace(/(w?)/g,function(match,p1){
       return p1 ? ['日', '一', '二', '三', '四', '五', '六'][day]:''
    })

    return fmt
}