merge.flow.yaml

collections:
  example/reductions/merge:
    schema:
      type: object
      reduce: { strategy: merge }
      properties:
        key: { type: string }
        value:
          # Merge only works with types "array" or "object".
          # Others will error at build time.
          type: [array, object]
          reduce: { strategy: merge }
          # Deeply merge sub-locations (items or properties) by summing them.
          items:
            type: number
            reduce: { strategy: sum }
          additionalProperties:
            type: number
            reduce: { strategy: sum }
      required: [key]
    key: [/key]

tests:
  example/reductions/test/deep-merge-array:
    - ingest:
        collection: example/reductions/merge
        documents:
          - { key: "key", value: [1, 1] }
          - { key: "key", value: [2, 2, 2] }
    - verify:
        collection: example/reductions/merge
        documents:
          - { key: "key", value: [3, 3, 2] }

  example/reductions/test/deep-merge-objects:
    - ingest:
        collection: example/reductions/merge
        documents:
          - { key: "key", value: { "a": 1, "b": 1 } }
          - { key: "key", value: { "a": 1, "c": 1 } }
    - verify:
        collection: example/reductions/merge
        documents:
          - { key: "key", value: { "a": 2, "b": 1, "c": 1 } }