How to use data transformers in Retool?

Using Data Transformers in Retool

Data transformers in Retool are a powerful feature that lets you manipulate and shape your data from queries like SQL, REST API, GraphQL, etc., before using it in your Retool app. This detailed guide covers how to effectively employ data transformers in your projects.

Accessing Your Retool Environment

• Log into your Retool account and navigate to the app where you want to utilize data transformers.
• Ensure you have the necessary queries or data sources set up in your Retool application.

Creating a New Query

• Within your Retool app, click on the "Resource" button to add a new resource, selecting the type that best matches your data source (SQL, REST, etc.).
• Provide all the necessary details and test the connection to ensure your query is functioning correctly.

Setting Up a Data Transformer

• Once your data source is active, click on the query panel of the desired query to open its settings.
• Locate the "Transformer" section, typically found under the "Query" tab.
• Click "Add transformer" to create a new transformer script. This will open a code editor where you can write JavaScript to process your data.

Writing and Testing Transformer Logic

• Use JavaScript in the transformer editor to manipulate your query data. The data returned by your query is automatically available as the variable data.
• For example, you can map over an array to format dates or filter data:

        return data.map(row => {
          row.formattedDate = new Date(row.dateField).toLocaleDateString();
          return row;
        }).filter(row => row.isActive);
      

• Test your transformer by using the "Run" button to ensure it returns the expected results. The panel will show the transformed data.

Utilizing Transformed Data

• Once your data is transformed, it can now be directly used in Retool components.
• Bind the output of your transformer to components by referencing the transformed data using {{ queryName.data }}.
• Example: Bind a table component to display your transformed data.

Debugging Transformers

• If your transformed data isn't behaving as expected, use console logging within your transformer script to troubleshoot.

        console.log(data);
        console.log(transformedData);
      

• Check for errors in the transformer script editor, and ensure any logical operations (like filtering or mapping) are correctly applied.

Advanced Data Manipulations

• For more complex data manipulations, consider using libraries like Lodash. Include them by pasting their script URLs in the HTML section of your Retool app settings.
• Include necessary documentation or helper comments within your script to maintain clarity as logic complexity increases.

Deploying Your Retool Application

• Once your transformers are implemented and validated, publish your application by moving it from the editor to production status.
• Ensure all your data displays correctly on production as intended and re-test all components’ bindings with the transformed data.

This guide provides a comprehensive overview for leveraging Retool’s data transformers, allowing you to dynamically and effectively manage data transformations directly inside your Retool applications. As you gain more experience, explore additional JavaScript functions to further extend your data manipulation capabilities.