# JavaScript Node
The **JavaScript Node** is a built‑in **Custom Extension** provided by ONEWEB that allows developers to execute **JavaScript logic** on data contained within **Business Objects (BO)** during **Microflow** or **Process Flow** execution.
This node enables **lightweight, inline scripting** for custom transformations, calculations, and conditional logic, without the need to create Java Tasks or manage external libraries.
JavaScript Node is intended for **simple, localized logic** that complements the visual flow design.
***
### Purpose of JavaScript Node
The JavaScript Node is designed to:
* Execute custom JavaScript logic within a flow
* Perform data transformation or calculation on Business Objects
* Implement logic that is difficult or verbose using standard nodes
* Avoid creating Java Tasks for lightweight scripting needs
#### Typical Use Cases
* Calculating derived or intermediate values
* Transforming data formats (e.g. restructuring objects, formatting values)
* Applying custom validation or conditional rules
* Manipulating arrays or object structures
JavaScript Node allows developers to extend Microflows with minimal code while preserving a low‑code design approach.
***
### Installing the JavaScript Node Extension
Before the JavaScript Node can be used, the extension must be **installed and enabled** for the application.
To install the extension:
* Follow the steps described in **Section 6.4.16 – Custom Extensions**
* Install and enable the **JavaScript Node** extension for the target application
Once installed:
* The JavaScript Node appears in the **diagram palette**
* It can be used like any other standard activity node in Microflow or Process Designer
***
### Writing JavaScript Logic
JavaScript logic is defined in the **Extension Properties** of the JavaScript Node.
#### Function Signature
All JavaScript logic must follow the required function signature:
```
function execute(input) {
// custom logic here
return answered;
}
```
Where:
* `input` contains the mapped **Business Objects**
* The function **must return a variable named `answered`**
* The returned value becomes the **output of the JavaScript Node**
This strict contract ensures consistent integration with downstream flow logic.
***
### Input Mapping (Business Objects)
All Business Objects that need to be processed by the JavaScript Node must be mapped as **input variables**.
Input mapping allows developers to:
* Select one or more Business Objects as inputs
* Pass structured data into the JavaScript function via the `input` parameter
Mapped Business Objects become accessible inside the JavaScript logic for processing and transformation.
***
### Output Mapping
The output of the JavaScript Node is defined by the returned variable **`answered`**.
Key characteristics:
* The output variable name is always **`answered`**
* Output data is available under the **Output Variable Object**
* Output values can be mapped to:
* Downstream Business Objects
* Gateway conditions
* UI components
* Database or Web Service tasks
This makes the JavaScript Node suitable for inline data enrichment and preparation.
***
### Using JavaScript Results in Flow Logic
Common integration patterns involving the JavaScript Node include:
* Transforming data before a Database or Web Service Task
* Calculating intermediate values used by a Gateway Node
* Preparing response data for UI or API output
* Enriching Business Object data during flow execution
The JavaScript Node integrates naturally into both **Microflow** and **Process Flow** execution models.
***
### Best Practices
To ensure maintainable and reliable scripting within Microflows:
* Use JavaScript Node for **lightweight logic only**
* Keep scripts short, readable, and well‑structured
* Avoid complex business logic—use Microflow structure or Java Nodes instead
* Always return output using the `answered` variable
* Validate and handle null or missing input values gracefully
Following these practices keeps Microflows clean and predictable.
***
### Summary
The **JavaScript Node** is a built‑in Custom Extension that enables **inline JavaScript execution** within ONEWEB Microflows and Processes.
With JavaScript Node, developers can:
* Execute custom JavaScript logic
* Transform and enrich Business Object data
* Implement flexible, fast‑iteration logic
* Avoid unnecessary Java development for simple cases
JavaScript Node is ideal for **data transformation and lightweight logic**, providing a practical balance between low‑code configuration and scripting flexibility in modern integration workflows.
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