$concatArrays
Reference group: Array aggregation expressions
What it does
Concatenates arrays in order.
Syntax
{$concatArrays: [array1, array2, ...]}
Use case
Combine stored and derived entries.
$concatArrays: practical example
{ $project: { all: { $concatArrays: [{ $ifNull: ["$tags", []] }, ["featured"]] } } }💡 Explanation
Concatenates arrays in order.
When to use it
Combine stored and derived entries.
Key Takeaways
- Concatenates arrays in order.
- Typical use: Combine stored and derived entries.