for (let i = ; i < batchTimes; i++) {

const promise = db.collection('EXAM').skip(i * MAX_LIMIT).limit(MAX_LIMIT).get()

tasks.push(promise)

}

return (await Promise.all(tasks)).reduce((acc, cur) => {

return {

data: acc.data.concat(cur.data),

errMsg: acc.errMsg,

}

})