// This file is autogenerated, DO NOT EDIT
// Use `node scripts/generate-docs-examples.js` to generate the docs examples

[source, js]
----
const response = await client.transform.previewTransform({
  id: "index_compare",
  source: {
    index: ["index1", "index2"],
    query: {
      match_all: {},
    },
  },
  dest: {
    index: "compare",
  },
  pivot: {
    group_by: {
      "unique-id": {
        terms: {
          field: "<unique-id-field>",
        },
      },
    },
    aggregations: {
      compare: {
        scripted_metric: {
          map_script: "state.doc = new HashMap(params['_source'])",
          combine_script: "return state",
          reduce_script:
            ' \n            if (states.size() != 2) {\n              return "count_mismatch"\n            }\n            if (states.get(0).equals(states.get(1))) {\n              return "match"\n            } else {\n              return "mismatch"\n            }\n            ',
        },
      },
    },
  },
});
console.log(response);
----