[source, ruby]
----
response = client.search(
  index: 'sales',
  body: {
    size: 0,
    runtime_mappings: {
      'price.adjusted' => {
        type: 'double',
        script: "\n        double price = doc['price'].value;\n        if (doc['promoted'].value) {\n          price *= 0.8;\n        }\n        emit(price);\n      "
      }
    },
    aggregations: {
      max_price: {
        max: {
          field: 'price.adjusted'
        }
      }
    }
  }
)
puts response
----
