Mongodb怎样更新像这样的文档，数组里面有子文档

更新数组字段使用$push关键词
提供参考代码：使用node.js
var filter;
if (paramtype === 1) {
filter = {helpapiuuid: helpapiuuid, "requests.paramid": opts.paramid};
} else {
filter = {helpapiuuid: helpapiuuid, "responses.paramid": opts.paramid};
}
var update;
if (paramtype === 1) {
update = {
$set: {
"requests.$.param": opts.param,
"requests.$.type": opts.desc,
"requests.$.desc": opts.desc,
"requests.$.default": opts.default
}
};
} else {
update = {
$set: {
"responses.$.param": opts.param,
"responses.$.type": opts.desc,
"responses.$.desc": opts.desc,
"responses.$.default": opts.default
}
};
}

return publicdb.collection(colname).findOneAndUpdateAsync(filter, update, {upsert: false})