JavaScript script

The JavaScript script component runs your JavaScript for every record that reaches it, on Google's V8 engine. async/await, fetch, timers and console work as you expect.

What you write

Connect the input and output first, then open the editor. The template is generated from the connections:

async function execute(metaData, inputData) {
	const outputData = new CustomerDto();
	services.Next(metaData, outputData);
}

Every type of the flow is a JavaScript class with the same property names (inputData.Email).

How it runs

• The script loads once when the flow starts. Top-level code runs then, and global variables keep their values between records.
• For every record the component calls execute(metaData, inputData) and waits until it finishes.
• Each component handles one record at a time.

Sending records on

services.Next(metaData, obj) sends a record to the components connected to Output; call it once, several times or not at all. obj is an instance of a flow class (new CustomerDto()), not a plain object. await services.NextAsync(metaData, obj) waits until the record is delivered.

Values

Flow type	In JavaScript
List	An array: length, for...of, map, filter, push, splice; assign a whole array to replace it
Date	Date
Decimal	number; assign a string ("12345678901234.123") for an exact decimal

What's available

• services: the flow services, with the C# member names. Methods that return a .NET Task return a promise.
• fetch(url, { method, headers, body }): works like in a browser. An object body is sent as JSON. HTTP error statuses come back as a response with ok false.
• console: log, info, warn, error and trace write to the designer's trace console.
• Timers: setTimeout, setInterval, and sleep(ms).
• crypto.

There are no modules: require, import and npm packages are not available.

Debugger

Start the flow with Debug (Ctrl+F5) and set breakpoints in the editor margin. The debugger stops on them and shows the local variables. Step with F10, F11 and Shift+F11; continue with F5.

Errors

An error that leaves execute goes to the flow's error handling, with your script's stack and the error line marked in the editor. To report an error and carry on, catch it and call await services.HandleExceptionAsync(metaData, inputData, error).

Example

let counter = 0;

async function execute(metaData, inputData) {
	if (!inputData.Email) return;          // filtered out
	const outputData = new CustomerDto();
	outputData.Name = inputData.Name.toUpperCase();
	outputData.Email = inputData.Email.toLowerCase();
	counter++;
	services.Messaging.UpdateStatusMessage(`Mapped ${counter}: ${outputData.Email}`);
	services.Next(metaData, outputData);
}