> ## Documentation Index > Fetch the complete documentation index at: https://docs.versori.com/llms.txt > Use this file to discover all available pages before exploring further. # Transformer > The transformer action is a drag and drop action that allows you to transform the data in your workflow. The transformer takes a source input and a target output, allowing you to expand objects, iterate over arrays, and use selectors from previous nodes in your boards. ### Initial Configuration The initial configuration of transformer assumes the source and target are the nearest connected nodes. To initialise the transformer, click configure: {" "}

#### Override Input Additionally - you can configure the input to be from any previous node in your flow. Furthermore, you can select parts of data from a previous node. The only restriction is that the data you select must be an `object` type. {" "}

### Initial View - Leaf (Source/Target) Nodes The initial view of the transformer is the leaf nodes, these are the source and target nodes. The source node is the data that is being transformed, and the target node is the output of the transformer. The source node is defined as per the above initial configuration or the overridden input. The target node is defined by the next connected node in the flow. {" "}

### Getting Started The Transformer has multiple tools available to help navigate your data tree and to help deal with nested objects and arrays iterations. You can drag an edge (line) between two properties to connect them. This will map these two properties together. You can also add tools by hovering over the circles on the properties and clicking on the plus button that appears, bringing out the tool menu and clicking on one of the tool names. {" "}

### Expanding objects Object properties can be expanded in both source and target nodes. Expanding an object property will allow you to access the properties of the object as individual properties in the transformer: {" "}

### Handling arrays/lists The Transformer has 3 tools currently for working with arrays/lists: `For Each`, `List Builder` and `List Generator`. #### For Each The `For Each` tool allows you to iterate over an array and perform actions on each item in the array. This tool can only be used as a source tool and must be used in conjunction with the [List Generator](#list-generator) tool. {" "}

#### List Generator The `List Generator` allows you to generate a list of items, this tool must be used alongside the `For Each` tool - so that on every iteration of the `For Each` tool, it will generate a new item in the list. This tool can only be used as a target tool. {" "}

#### List Builder The `List Builder` tool allows you to manually build a list of items - for example if you want to build a list with only one element, using parent properties of the source. This tool should be used as a target tool. You can click on the plus button at the bottom of the tool to add another element to the list. {" "}

### Other Tools Additionally - there is also a `Selector` tool, which allows you to step back out of the tranformer and select a value from a previous node in your board. This tool should be used as a target tool. {" "}

And finally there's the `Constant` tool, which allows you to add a constant value to your transformer. The type is based on the type of the property you're connecting to. This tool should also be used as a target tool. {" "}

### Validation The transformer will validate your configuration as you go, and will highlight any errors in red. Currently this just validates the property data type.

### That's it! All of these tools will allow you to build up a complex transformation of your data, empowering you to build powerful workflows. {" "}