SOURCE

let data= [
    {"id":"377771466851848193","courseId":"371713782906064900","weekDayCode":"1","startTime":"08:30","endTime":"10:00"},
    {"id":"377771466851848194","courseId":"371713782906064900","weekDayCode":"1","startTime":"10:15","endTime":"10:30"},
    {"id":"377771466851848195","courseId":"371713782906064900","weekDayCode":"1","startTime":"08:00","endTime":"08:45"},
]
console.log(data);


function verify() {
    for(let i in data) {
        for(let j in data) {
            if(i !== j) {
                let item = data[i];
                let item_ = data[j];
                if(
                    (getMinute(item_.startTime) > getMinute(item.startTime) && getMinute(item_.startTime) < getMinute(item.endTime))
                    ||
                    (getMinute(item_.endTime) > getMinute(item.startTime) && getMinute(item_.endTime) < getMinute(item.endTime))
                ) {
                    console.log(`第${Number(j)+1}条格式有误`)
                    return false;
                }
            }
        }
    };
    console.log(`格式无误`)
    return true
}

function getMinute(time) {
    if(!time) {
        return 0
    };
    let arr = time.split(':');
    return Number(arr[0])*60 + Number(arr[1]);
} 

<button onclick="verify()" >Verify</button>