javascript-skill

name	javascript-skill
description	Execute JavaScript code for calculations, data processing, and JSON manipulation. Full ES6+ support with Node.js runtime.
allowed-tools	javascript_executor
metadata	{"author":"machina","version":"1.0","category":"code"}

JavaScript Code Execution Tool

Execute JavaScript code for calculations, data processing, and JSON manipulation.

How It Works

This skill provides instructions for the JavaScript Executor tool node. Connect the JavaScript Executor node to Zeenie's input-tools handle to enable JavaScript code execution.

javascript_code Tool

Execute JavaScript code and return results.

Schema Fields

Field	Type	Required	Description
code	string	Yes	JavaScript code to execute

Available Features

Feature	Description
ES6+ syntax	Arrow functions, destructuring, spread operator
JSON	JSON.parse() and JSON.stringify()
Math	Mathematical operations
Date	Date and time manipulation
Array methods	map, filter, reduce, sort, etc.
Object methods	keys, values, entries, assign
String methods	All standard string methods

Built-in Variables

Variable	Description
input_data	Data from connected workflow nodes (object)
output	Set this to return a result

Output Methods

1. Set output variable: Returns structured data to the workflow
2. Use console.log(): Captured as console output

Examples

Basic calculation:

{
  "code": "const result = 25 * 4 + 10;\nconsole.log(`Result: ${result}`);\noutput = result;"
}

Array processing:

{
  "code": "const numbers = input_data.numbers || [1, 2, 3, 4, 5];\nconst total = numbers.reduce((a, b) => a + b, 0);\nconst average = total / numbers.length;\nconsole.log(`Total: ${total}, Average: ${average}`);\noutput = { total, average };"
}

Filter array:

{
  "code": "const numbers = input_data.numbers || [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];\nconst evens = numbers.filter(n => n % 2 === 0);\nconsole.log(`Even numbers: ${evens}`);\noutput = evens;"
}

Transform data:

{
  "code": "const users = input_data.users || [{name: 'John', age: 30}, {name: 'Jane', age: 25}];\nconst names = users.map(u => u.name);\nconsole.log(`Names: ${names.join(', ')}`);\noutput = names;"
}

JSON manipulation:

{
  "code": "const data = { name: 'John', age: 30, city: 'NYC' };\nconst json = JSON.stringify(data, null, 2);\nconsole.log(json);\noutput = data;"
}

Object operations:

{
  "code": "const obj = { a: 1, b: 2, c: 3 };\nconst keys = Object.keys(obj);\nconst values = Object.values(obj);\nconst sum = values.reduce((a, b) => a + b, 0);\nconsole.log(`Sum of values: ${sum}`);\noutput = { keys, values, sum };"
}

Date operations:

{
  "code": "const now = new Date();\nconst tomorrow = new Date(now.getTime() + 24 * 60 * 60 * 1000);\nconst formatted = tomorrow.toISOString().split('T')[0];\nconsole.log(`Tomorrow: ${formatted}`);\noutput = formatted;"
}

Sort array:

{
  "code": "const items = input_data.items || ['banana', 'apple', 'cherry'];\nconst sorted = [...items].sort();\nconsole.log(`Sorted: ${sorted}`);\noutput = sorted;"
}

String processing:

{
  "code": "const text = 'Hello World, Hello JavaScript';\nconst words = text.split(' ');\nconst unique = [...new Set(words)];\nconsole.log(`Unique words: ${unique}`);\noutput = unique;"
}

Destructuring and spread:

{
  "code": "const { name, age } = input_data.user || { name: 'John', age: 30 };\nconst profile = { name, age, active: true };\nconst extended = { ...profile, role: 'admin' };\nconsole.log(JSON.stringify(extended));\noutput = extended;"
}

Response Format

Success:

{
  "success": true,
  "result": { "total": 15, "average": 3 },
  "output": "Total: 15, Average: 3"
}

Error:

{
  "error": "ReferenceError: undefinedVar is not defined"
}

Use Cases

Use Case	Approach
Array manipulation	Use map, filter, reduce
JSON processing	Use JSON.parse, JSON.stringify
Object operations	Use Object.keys, values, entries
String processing	Use split, join, replace
Math calculations	Use Math methods
Date operations	Use Date object
Data transformation	Use spread and destructuring

Guidelines

1. Always set output: This returns data to the workflow
2. Use console.log() for debugging: Output is captured and returned
3. Use ES6+ features: Arrow functions, destructuring, spread
4. Handle undefined: Use || defaultValue pattern
5. Keep code focused: One task per execution
6. No network access: Use http-skill for web requests
7. Timeout: Default 30 seconds max execution time

Security Restrictions

• No network/fetch operations
• No file system access (no require('fs'))
• No child processes
• Limited execution time (30 seconds)
• Sandboxed environment

Common Patterns

Default values:

const data = input_data.value || 'default';

Null-safe access:

const name = input_data?.user?.name || 'Unknown';

Array to object:

const arr = [{id: 1, name: 'A'}, {id: 2, name: 'B'}];
const obj = Object.fromEntries(arr.map(x => [x.id, x.name]));

Setup Requirements

1. Connect the JavaScript Executor node to Zeenie's input-tools handle
2. Node.js must be installed on the server