$setUnion/$setIntersection/$setDifference/$setEquals
Reference group: Object and set expressions
What it does
Performs set operations; output order is not guaranteed.
Syntax
Set expressions take arrays
Use case
Compare tags, permissions, or skills.
$setUnion/$setIntersection/$setDifference/$setEquals: practical example
{ $project: { common: { $setIntersection: ["$requested", "$granted"] } } }💡 Explanation
Performs set operations; output order is not guaranteed.
When to use it
Compare tags, permissions, or skills.
Key Takeaways
- Performs set operations; output order is not guaranteed.
- Typical use: Compare tags, permissions, or skills.