Skip to Content
StepsObject Transformer

Object Transformer (ObjectTransformer)

The ObjectTransformer step allows you to shape and combine data from previous steps into a final JSON output (or intermediate format). It’s the perfect place to do last-minute data transformations or merges before returning results to the user.

Overview

When you define an ObjectTransformer step:

{
  id: 'finalResult',
  type: 'ObjectTransformer',
  result: {
    '@Extend': '$.results.someGenerator',
    extraField: 'someValue',
  },
}
  • id: Unique identifier (e.g. finalResult).
  • type: Must be ObjectTransformer.
  • result: An object that can contain references or operators (@Map, @Extend, etc.). This is processed via the same Flow Language & JSON Path rules used elsewhere.

Why Use Object Transformer?

  • Consolidate results from multiple steps into one final object.
  • Rename or re-map fields using JSON Path.
  • Combine data for your UI’s final display or for a subsequent step.
  • Apply advanced transformations (like @Map, @Index, @Extend) to reformat data from prior steps.

Example

{
  id: 'finalResult',
  type: 'ObjectTransformer',
  result: {
    '@Extend': '$.results.objectGeneratorStep',
    info: {
      modelUsed: '$.results.myTrainingStep.id',
      images: '$.results.imageStep.images',
    },
  },
}

Explanation:

  1. @Extend: merges the entire object from objectGeneratorStep into the final result.
  2. modelUsed: references myTrainingStep.id.
  3. images: references imageStep.images.

Final should look like:

{
  someField: 'original data from objectGeneratorStep',
  anotherField: 42,
  info: {
    modelUsed: 'uuid-of-the-model',
    images: [{ url: '...' }, { url: '...' }],
  },
}

Step Definition

{
  id: 'someTransformer',
  type: 'ObjectTransformer',
  result: {
    mergedStuff: {
      '@Extend': '$.results.stepA',
    },
    newArray: [
      [
        '@Map($.results.stepB.arrayField)',
        {
          title: '$$.title',
          desc: '$$.description',
        },
      ],
    ],
  },
}

The result field is processed with the Flow Language, so you can do everything from map loops to merging objects.

Parameters

Unlike other steps, ObjectTransformer uses: • result (required): The structure you want to build or transform. • No typical “settings” or “parameters” object is needed.

Internally, it just transforms or merges data and places it into results.[transformerId].

Common Use Cases

  • Final Assembly: Combining all relevant pieces from your Flow into one object for UI display (like a summary page).
  • Data Filtering: If you only need certain fields from a complex prior step, you can pick them out in result.
  • Re-Structuring: Possibly you want to produce a simpler shape for an API or for a subsequent Zipper step.
  • Intermediate: Sometimes you can have multiple ObjectTransformer steps chained if your data transformations are large or you prefer them in smaller chunks.
Last updated on