search for a data if not exist then append array in mongo code example
Example: mongodb add to array if not exists
db.tags.update(
{name: 'sport'},
{$addToSet: { videoIDs: "34f54e34c" } }
);
db.tags.update(
{name: 'sport'},
{$addToSet: { videoIDs: "34f54e34c" } }
);