Given: a document as below
{
_id: ObjectId("5eb...."),
jobId: '40297467',
aliases: [aX1, bX2_0, cX1X9_0]
}
When: combinations X1...X9 are not welcome in any of aliases
Then: I want to have a mongo native elegant way to replace an appropriate regex pattern with an empty string, so, as a result, I have the document as below:
{
_id: ObjectId("5eb...."),
jobId: '40297467',
aliases: [a, b_0, c_0]
}
Homework done:
Here MONGO mongodb script to replace a substring from a array element there is a solution for cases where you do not need pattern and have a simple string to replace, however, it is of not much use - since aggregation replaceAll find argument "any valid expression that resolves to a string or a null" (https://docs.mongodb.com/manual/reference/operator/aggregation/replaceAll/) So, if I use pattern it just does not work.
mongo forEach loop does the job but it looks a bit ugly for me... Besides, I'm not sure what will be the price of such looping.
db.col.find({ jobId: "40297467" }).forEach(function (x) {
const regex = /*pattern*/gi;
array = []
for (let alias of x.aliases) {
array.push(alias.replace(regex, ""));
}
db.col.update({ _id: x._id }, { $set: { aliases: array} });
});
Any help would be much appreciated :)
This update with aggregation pipeline works with MongoDB v4.4 (uses the $function aggregate operator):
db.collection.updateMany(
{ },
[
{
$set: {
aliases: {
$function: {
body: function(arr) {
arr = arr.map(e => e.replace(/x\d/gi, ""));
return arr;
},
args: [ "$aliases" ],
lang: "js"
}
}
}
}
])