Condensing similar IF statements

I know there has to be a better way than this:

if (mon_open_close_hours=='12:00-12:00'){
    mon_open_close_hours='24hrs';
}
if (tue_open_close_hours=='12:00-12:00'){
    tue_open_close_hours='24hrs';
}
if (wed_open_close_hours=='12:00-12:00'){
    wed_open_close_hours='24hrs';
}
if (thu_open_close_hours=='12:00-12:00'){
    thu_open_close_hours='24hrs';
}
if (fri_open_close_hours=='12:00-12:00'){
    fri_open_close_hours='24hrs';
}
if (sat_open_close_hours=='12:00-12:00'){
    sat_open_close_hours=['24hrs'];
}
if (sun_open_close_hours=='12:00-12:00'){
    sun_open_close_hours=['24hrs'];
}

Is there a way to condense this somehow?

I've tried this, but it returns '12:00-12:00' for everything

var $variables = [mon_open_close_hours,tue_open_close_hours,wed_open_close_hours,thu_open_close_hours,fri_open_close_hours,sat_open_close_hours,sun_open_close_hours];
     $variables.map(function(val) {
        if(val=='12:00-12:00'){
            val=['24hrs'];
        }
    })