Execute Script

Basic usage​

Execute Script runs the configured script in the chosen JavaScript engine.

Configuration​

The node's property panel:

×

Name​

The name shown on the canvas, used to identify this processor within the workflow.

Description​

Explains what this processor is for, making the workflow easier to read.

Properties​

Engine (required)​

The JavaScript engine. Only ECMA5 is supported at present.

Script (required)​

The JavaScript to run.

Accessing data

Execute Script exposes a global object named payload holding everything in the workflow:

• the current workflow's payload data
• built-in variables such as prevMessage and prevPayload

Reading data

Given this data in your workflow:

{
  "user": {
    "name": "Alice",
    "email": "zhang@example.com"
  }
}

read it like this:

// "Alice"
const userName = payload.user.name
 
// "zhang@example.com"
const userEmail = payload.user.email

Modifying data

You can also modify the payload, and the changes carry into later processors:

// change existing data
payload.user.name = "Bob"
 
// add data
payload.processedAt = new Date().toISOString()
payload.status = "completed"

Built-in variables

Asgard's built-in variables are reachable through payload:

// the user's last message
const lastMessage = payload.prevMessage
 
// the previous processor's payload
const previousData = payload.prevPayload
 
// nested data
const specificValue = payload.prevPayload.someProperty

Limitations

Asgard's built-in functions (history(), vecToStr() and the like) are not available inside Execute Script. Use another processor type when you need them.

In the Workflow CRD​

- name: proc-transform
  type: execute-script
  labels:
    display_name: Tidy the query result
  configs:
    - name: engine
      value: javascript
    - name: script
      expression: |-
        (() => {
          return rows.map(r => r.name).join(", ");
        })()

Relationships​

Success​

Once the script finishes, the workflow continues from this connection point. The script's result is not predictable.

Failure​

If the script errors, the workflow continues from this connection point and a prevError variable holds the error.

A worked example​

Turn an array from the previous step into one sentence.

var names = [];
for (var i = 0; i < low_stock.length; i++) {
  names.push(low_stock[i].sku_name);
}
return names.join('、');

That is var and a for loop rather than const and map because the engine is ECMA5.

Notes​

• Engine has exactly one valid value, ECMA5, running on goja. Anything else gives Unknown script engine.
• Being ECMA5, post-ES6 syntax is out: no arrow functions, no let/const, no template literals.