# 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 execution.
This node enables lightweight, inline scripting for **custom transformations, calculations, and conditional logic** without requiring Java code or external libraries.
***
### 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 simple scripting needs
Typical use cases include:
* Calculating derived values
* Transforming data formats
* Applying custom validation or conditional rules
* Manipulating arrays or object structures
***
### Install JavaScript Node Extension
Before using the JavaScript Node, the extension must be **installed and enabled** in 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 application
Once installed, the JavaScript Node becomes available in the **diagram palette** like any other activity node.
***
### Writing JavaScript Logic
JavaScript logic is configured in the **Extension Properties** of the JavaScript Node.
#### Function Signature
Users must define the logic using the following function signature:
```
function execute(input) {
// custom logic here
return answered;
}
```
* `input` contains the mapped Business Objects
* The function must return a variable named **answered**
* The returned value becomes the node’s output
***
### Input Mapping (Business Objects)
All Business Objects that need to be processed by the JavaScript logic must be mapped as **input variables**.
Steps:
1. Open **Mapping Parameter**
2. Add all required Business Objects under **Input Variable**
3. Use the **lookup** option to select existing Business Objects
The mapped Business Objects are passed into the JavaScript function via the `input` parameter.
***
### Output Mapping
The output of the JavaScript Node must be returned using the variable named **answered**.
* The output data is available under the **Output Variable Object**
* The output variable name is always **answered**
* Output values can be mapped to:
* Downstream Business Objects
* Gateway conditions
* UI components
* Database or service calls
***
### Using JavaScript Results in Flow Logic
Common integration patterns include:
* Transforming data before a Database or Web Service Task
* Calculating intermediate values for decision logic
* Feeding processed data into a **Gateway Node**
* Preparing response structures for UX/UI
The JavaScript Node fits naturally into both **Microflow** and **Process Flow** execution models.
***
### Best Practices
* Use JavaScript Node for **lightweight logic only**
* Keep scripts readable and maintainable
* Avoid complex business logic—use Microflow structure where possible
* Always return data as **answered**
* Validate and handle null or missing input values
***
### JavaScript Node vs Java Task
| JavaScript Node | Java Task |
| --------------------- | ----------------------------- |
| Lightweight scripting | Full Java implementation |
| No external JARs | Requires JAR packaging |
| Faster setup | More flexible & powerful |
| Best for small logic | Best for complex integrations |
***
### Summary
The **JavaScript Node** is a built‑in Custom Extension that enables **inline scripting** using JavaScript within ONEWEB Microflows.
With the JavaScript Node, developers can:
* Execute custom JavaScript logic
* Transform and enrich Business Object data
* Implement flexible, fast iteration logic
* Avoid unnecessary Java code for simple cases
This node is ideal for **data transformation and lightweight business logic** in modern integration workflows.
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