SOURCE

let usedTime = '20分钟10秒'
let usedTime1 = '10秒'


function format(usedTime) {
    let m;
    let s;
    if(usedTime.split('').includes('分')) {
        let arr = usedTime.split('分钟') 
        m = arr[0]
        s=  arr[1].replace(/秒/,'')
    }else {
         let arr = usedTime.split('秒') 
         s = arr[0]
    }

    return {
        m,s
    }
}

console.log(format(usedTime).m,format(usedTime).s)
console.log(format(usedTime1).m,format(usedTime1).s)