How can graaljs not merge Array?

[k1tano]

script like "const avgSendReceiveDiff = db.chatGptMessage.aggregate([
{
$project: {
created_by: 1,
timeDifference: { $subtract: ["$receive_time", "$send_time"] }
}
},
{
$group: {
_id: "$created_by",
avgTimeDifference: { $avg: "$timeDifference" }
}
}
])"
When i use context.eval("js",script)
I expected the "$subtract: ["$receive_time", "$send_time"]" stay unchanged and mongo java driver can parse, but when i extract the string, it was serialize into " $subtract: Array(2)", and mongodb can not parse.
How can i fix this?

[woess]

I suppose you got that from Value.toString()? That string representation is not supposed to be consumed by applications. You can use various Value methods (like getMember(), getMemberKeys(), getArrayElement(), getArraySize()) to access object members and array elements, or use JSON.stringify to convert an object back into a string.