Coding HubItems

A Coding HubItem contains reusable JavaScript for calculations and transformations that are clearer in code than in a table or visual rule. It executes in a secure platform sandbox with access to the modeled input, output, and supported execution context.

Use Coding for deterministic business logic. Use HTTP Client or connector nodes for network calls, and use a Workflow to orchestrate several steps.

Configure the contract

Select input and output Data Models in Settings. The Rich Editor uses those models to suggest paths and reduce spelling errors. A Coding HubItem should return only fields described by its output model.

Example input model:

{
  "subtotal": 1250,
  "discountPercent": 0.1,
  "taxRate": 0.15,
  "currency": "NZD"
}

Example output model:

{
  "discountAmount": 125,
  "taxableAmount": 1125,
  "taxAmount": 168.75,
  "total": 1293.75,
  "currency": "NZD"
}

Worked example: calculate an order total

In the Rich Editor, calculate each intermediate value explicitly:

const subtotal = Number(input.subtotal || 0);
const discountPercent = Number(input.discountPercent || 0);
const taxRate = Number(input.taxRate || 0);

const discountAmount = subtotal * discountPercent;
const taxableAmount = subtotal - discountAmount;
const taxAmount = taxableAmount * taxRate;

output.discountAmount = Math.round(discountAmount * 100) / 100;
output.taxableAmount = Math.round(taxableAmount * 100) / 100;
output.taxAmount = Math.round(taxAmount * 100) / 100;
output.total = Math.round((taxableAmount + taxAmount) * 100) / 100;
output.currency = input.currency;

For financial calculations, agree on rounding rules with the business owner and test values that produce fractional cents. Do not assume the example rounding policy is correct for every jurisdiction.

Input, output, and context

• input contains the request mapped into the Coding HubItem.
• output is the modeled result returned to the caller or next workflow node.
• The supported execution context can expose controlled value updates through suggestions in the Rich Editor.

Use local constants for intermediate calculations and write intentional final fields to output. This makes debugging easier than mutating input throughout the script.

Sandbox boundaries

Code is not running in a web browser or a general-purpose server process. Do not rely on:

• browser objects or page state;
• installed packages or module imports;
• local files or operating-system commands;
• unrestricted outbound network requests;
• shared memory surviving between executions.

These restrictions make execution predictable and keep tenant data isolated. Use modeled inputs, Global Variables for non-secret runtime configuration, connectors for credentials, and HTTP Client nodes for outbound calls.

Defensive code

Validate assumptions before calculation. For example:

if (input.subtotal == null || Number(input.subtotal) < 0) {
  throw new Error("subtotal must be a non-negative number");
}

if (input.discountPercent < 0 || input.discountPercent > 1) {
  throw new Error("discountPercent must be between 0 and 1");
}

Prefer a clear error over silently returning a plausible but incorrect result. Avoid including secrets or unnecessary personal information in error messages because errors can appear in execution history.

Work with collections

A Coding HubItem can transform modeled collections. For example:

const items = input.items || [];
output.activeSkus = items
  .filter(item => item.active === true)
  .map(item => item.sku);
output.activeCount = output.activeSkus.length;

If the same transformation can be understood in a Workflow with Filter and mapping nodes, prefer the visual form for business transparency. Use Coding when it materially improves clarity.

Test the code

Save cases for:

• a normal valid request;
• zero values;
• missing optional fields;
• invalid negative or out-of-range numbers;
• empty and large collections;
• rounding boundaries;
• every explicit error path.

Debug mode shows the HubItem's input, output, and supported context changes. Never use production customer data as an informal test fixture.

Use Coding in a workflow

Add a Coding node, select the reusable Coding HubItem and version, and map inputs and outputs. Some workflow configurations may also offer inline code. Prefer a reusable HubItem when the logic is shared, independently tested, or important enough to version separately.

Common problems

Problem	Resolution
Suggested field is missing	Confirm the selected model and save its latest definition
Result field is absent	Assign it to output and include it in the output model
Number becomes text or NaN	Validate and convert the input type before calculation
Script works alone but not in a workflow	Inspect the incoming edge mappings and deployed Coding version
Network or package API is unavailable	Move the call to an HTTP Client/connector or rewrite with supported language features