n8n-code-javascriptlisted
Install: claude install-skill waseemnasir2k26/skynetlabs-all-claude-code
# JavaScript Code Node
Expert guidance for writing JavaScript code in n8n Code nodes.
---
## Quick Start
```javascript
// Basic template for Code nodes
const items = $input.all();
// Process data
const processed = items.map(item => ({
json: {
...item.json,
processed: true,
timestamp: new Date().toISOString()
}
}));
return processed;
```
### Essential Rules
1. **Choose "Run Once for All Items" mode** (recommended for most use cases)
2. **Access data**: `$input.all()`, `$input.first()`, or `$input.item`
3. **CRITICAL**: Must return `[{json: {...}}]` format
4. **CRITICAL**: Webhook data is under `$json.body` (not `$json` directly)
5. **Built-ins available**: $helpers.httpRequest(), DateTime (Luxon), $jmespath()
---
## Mode Selection Guide
The Code node offers two execution modes. Choose based on your use case:
### Run Once for All Items (Recommended - Default)
**Use this mode for:** 95% of use cases
- **How it works**: Code executes **once** regardless of input count
- **Data access**: `$input.all()` or `items` array
- **Best for**: Aggregation, filtering, batch processing, transformations, API calls with all data
- **Performance**: Faster for multiple items (single execution)
```javascript
// Example: Calculate total from all items
const allItems = $input.all();
const total = allItems.reduce((sum, item) => sum + (item.json.amount || 0), 0);
return [{
json: {
total,
count: allItems.length,
average: total / allItems.length
}
}];
```