$map
Reference group: Array aggregation expressions
What it does
Transforms each element into a new value or object.
Syntax
{$map: { input, as?, in }}
Use case
Compute per-element values.
$map: practical example
{ $project: { lines: { $map: { input: "$items", as: "i", in: { sku: "$$i.sku", total: { $multiply: ["$$i.price", "$$i.qty"] } } } } } }💡 Explanation
Transforms each element into a new value or object.
When to use it
Compute per-element values.
Key Takeaways
- Transforms each element into a new value or object.
- Typical use: Compute per-element values.