$addToSet
Reference group: Update operator families
What it does
Adds only if an equal value is absent.
Syntax
{$addToSet: { array: value }}
Use case
Set-like roles or tags.
$addToSet: practical example
db.users.updateOne({ _id: userId }, { $addToSet: { permissions: "reports:read" } })💡 Explanation
Adds only if an equal value is absent.
When to use it
Set-like roles or tags.
Key Takeaways
- Adds only if an equal value is absent.
- Typical use: Set-like roles or tags.