`op: filter`

Keep only array elements matching a where predicate (in-place).

Allowed phases

Phase	Status
`preflight`	✗ forbidden
`core`	✓ allowed
`side_effects`	✗ forbidden

Syntax

- op: filter
  path: /cart/items
  where: "it.quantity > 0"

Parameters

Field	Required	Description
`path`	yes	Array field path
`where`	yes	Plain string; `it` = current element

Behavior

Inverse of remove: matching elements are kept. where is a plain string.

See also

Operations index — all ops by phase
actions — rule structure and phases
Intents: Rules — narrative examples