N8n Code Javascript V2

---
name: n8n-code-javascript-v2
description: "JavaScript Code Node workflow skill. Use this skill when the user needs Write JavaScript code in n8n Code nodes. Use when writing JavaScript in n8n, using $input/$json/$node syntax, making HTTP requests with $helpers, working with dates using DateTime, troubleshooting Code node errors, or choosing between Code node modes and the operator should preserve the upstream workflow, copied support files, and provenance before merging or handing off."
version: "0.0.1"
category: cli-automation
tags: ["n8n-code-javascript-v2", "n8n-code-javascript", "write", "javascript", "n8n", "nodes", "use", "writing"]
complexity: advanced
risk: caution
tools: ["codex-cli", "claude-code", "cursor", "gemini-cli", "opencode"]
source: community
author: "sickn33"
date_added: "2026-04-25"
date_updated: "2026-04-25"
---

# JavaScript Code Node

## Overview

This public intake copy packages `plugins/antigravity-awesome-skills/skills/n8n-code-javascript` from `https://github.com/sickn33/antigravity-awesome-skills` into the native Omni Skills editorial shape without hiding its origin.

Use it when the operator needs the upstream workflow, support files, and repository context to stay intact while the public validator and private enhancer continue their normal downstream flow.

This intake keeps the copied upstream files intact and uses the `external_source` block in `metadata.json` plus `ORIGIN.md` as the provenance anchor for review.

# JavaScript Code Node Expert guidance for writing JavaScript code in n8n Code nodes. ---

Imported source sections that did not map cleanly to the public headings are still preserved below or in the support files. Notable imported sections: Mode Selection Guide, Data Access Patterns, Critical: Webhook Data Structure, Return Format Requirements, Common Patterns Overview, Built-in Functions & Helpers.

## When to Use This Skill

Use this section as the trigger filter. It should make the activation boundary explicit before the operator loads files, runs commands, or opens a pull request.

- ✅ Complex transformations requiring multiple steps
- ✅ Custom calculations or business logic
- ✅ Recursive operations
- ✅ API response parsing with complex structure
- ✅ Multi-step conditionals
- ✅ Data aggregation across items

## Operating Table

| Situation | Start here | Why it matters |
| --- | --- | --- |
| First-time use | `metadata.json` | Confirms repository, branch, commit, and imported path through the `external_source` block before touching the copied workflow |
| Provenance review | `ORIGIN.md` | Gives reviewers a plain-language audit trail for the imported source |
| Workflow execution | `SKILL.md` | Starts with the smallest copied file that materially changes execution |
| Supporting context | `SKILL.md` | Adds the next most relevant copied source file without loading the entire package |
| Handoff decision | `## Related Skills` | Helps the operator switch to a stronger native skill when the task drifts |

## Workflow

This workflow is intentionally editorial and operational at the same time. It keeps the imported source useful to the operator while still satisfying the public intake standards that feed the downstream enhancer flow.

1. Confirm the user goal, the scope of the imported workflow, and whether this skill is still the right router for the task.
2. Read the overview and provenance files before loading any copied upstream support files.
3. Load only the references, examples, prompts, or scripts that materially change the outcome for the current request.
4. Execute the upstream workflow while keeping provenance and source boundaries explicit in the working notes.
5. Validate the result against the upstream expectations and the evidence you can point to in the copied files.
6. Escalate or hand off to a related skill when the work moves out of this imported workflow's center of gravity.
7. Before merge or closure, record what was used, what changed, and what the reviewer still needs to verify.

### Imported Workflow Notes

#### Imported: 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
  }
}];
```

**When to use:**
- ✅ Comparing items across the dataset
- ✅ Calculating totals, averages, or statistics
- ✅ Sorting or ranking items
- ✅ Deduplication
- ✅ Building aggregated reports
- ✅ Combining data from multiple items

### Run Once for Each Item

**Use this mode for:** Specialized cases only

- **How it works**: Code executes **separately** for each input item
- **Data access**: `$input.item` or `$item`
- **Best for**: Item-specific logic, independent operations, per-item validation
- **Performance**: Slower for large datasets (multiple executions)

```javascript
// Example: Add processing timestamp to each item
const item = $input.item;

return [{
  json: {
    ...item.json,
    processed: true,
    processedAt: new Date().toISOString()
  }
}];
```

**When to use:**
- ✅ Each item needs independent API call
- ✅ Per-item validation with different error handling
- ✅ Item-specific transformations based on item properties
- ✅ When items must be processed separately for business logic

**Decision Shortcut:**
- **Need to look at multiple items?** → Use "All Items" mode
- **Each item completely independent?** → Use "Each Item" mode
- **Not sure?** → Use "All Items" mode (you can always loop inside)

---

## Examples

### Example 1: Ask for the upstream workflow directly

```text
Use @n8n-code-javascript-v2 to handle <task>. Start from the copied upstream workflow, load only the files that change the outcome, and keep provenance visible in the answer.
```

**Explanation:** This is the safest starting point when the operator needs the imported workflow, but not the entire repository.

### Example 2: Ask for a provenance-grounded review

```text
Review @n8n-code-javascript-v2 against metadata.json and ORIGIN.md, then explain which copied upstream files you would load first and why.
```

**Explanation:** Use this before review or troubleshooting when you need a precise, auditable explanation of origin and file selection.

### Example 3: Narrow the copied support files before execution

```text
Use @n8n-code-javascript-v2 for <task>. Load only the copied references, examples, or scripts that change the outcome, and name the files explicitly before proceeding.
```

**Explanation:** This keeps the skill aligned with progressive disclosure instead of loading the whole copied package by default.

### Example 4: Build a reviewer packet

```text
Review @n8n-code-javascript-v2 using the copied upstream files plus provenance, then summarize any gaps before merge.
```

**Explanation:** This is useful when the PR is waiting for human review and you want a repeatable audit packet.

### Imported Usage Notes

#### Imported: 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()

---

## Best Practices

Treat the generated public skill as a reviewable packaging layer around the upstream repository. The goal is to keep provenance explicit and load only the copied source material that materially improves execution.

- Always Validate Input Data ``javascript const items = $input.all(); // Check if data exists if (!items || items.length === 0) { return []; } // Validate structure if (!items[0].json) { return [{json: {error: 'Invalid input format'}}]; } // Continue processing...
- Use Try-Catch for Error Handling javascript try { const response = await $helpers.httpRequest({ url: 'https://api.example.com/data' }); return [{json: {success: true, data: response}}]; } catch (error) { return [{ json: { success: false, error: error.message } }]; } ### 3.
- Prefer Array Methods Over Loops javascript // ✅ GOOD: Functional approach const processed = $input.all() .filter(item => item.json.valid) .map(item => ({json: {id: item.json.id}})); // ❌ SLOWER: Manual loop const processed = []; for (const item of $input.all()) { if (item.json.valid) { processed.push({json: {id: item.json.id}}); } } ### 4.
- Filter Early, Process Late javascript // ✅ GOOD: Filter first to reduce processing const processed = $input.all() .filter(item => item.json.status === 'active') // Reduce dataset first .map(item => expensiveTransformation(item)); // Then transform // ❌ WASTEFUL: Transform everything, then filter const processed = $input.all() .map(item => expensiveTransformation(item)) // Wastes CPU .filter(item => item.json.status === 'active'); ### 5.
- Use Descriptive Variable Names javascript // ✅ GOOD: Clear intent const activeUsers = $input.all().filter(item => item.json.active); const totalRevenue = activeUsers.reduce((sum, user) => sum + user.json.revenue, 0); // ❌ BAD: Unclear purpose const a = $input.all().filter(item => item.json.active); const t = a.reduce((s, u) => s + u.json.revenue, 0); ### 6.
- Debug with console.log() `javascript // Debug statements appear in browser console const items = $input.all(); console.log(Processing ${items.length} items); for (const item of items) { console.log('Item data:', item.json); // Process...
- Keep the imported skill grounded in the upstream repository; do not invent steps that the source material cannot support.

### Imported Operating Notes

#### Imported: Best Practices

### 1. Always Validate Input Data

```javascript
const items = $input.all();

// Check if data exists
if (!items || items.length === 0) {
  return [];
}

// Validate structure
if (!items[0].json) {
  return [{json: {error: 'Invalid input format'}}];
}

// Continue processing...
```

### 2. Use Try-Catch for Error Handling

```javascript
try {
  const response = await $helpers.httpRequest({
    url: 'https://api.example.com/data'
  });

  return [{json: {success: true, data: response}}];
} catch (error) {
  return [{
    json: {
      success: false,
      error: error.message
    }
  }];
}
```

### 3. Prefer Array Methods Over Loops

```javascript
// ✅ GOOD: Functional approach
const processed = $input.all()
  .filter(item => item.json.valid)
  .map(item => ({json: {id: item.json.id}}));

// ❌ SLOWER: Manual loop
const processed = [];
for (const item of $input.all()) {
  if (item.json.valid) {
    processed.push({json: {id: item.json.id}});
  }
}
```

### 4. Filter Early, Process Late

```javascript
// ✅ GOOD: Filter first to reduce processing
const processed = $input.all()
  .filter(item => item.json.status === 'active')  // Reduce dataset first
  .map(item => expensiveTransformation(item));  // Then transform

// ❌ WASTEFUL: Transform everything, then filter
const processed = $input.all()
  .map(item => expensiveTransformation(item))  // Wastes CPU
  .filter(item => item.json.status === 'active');
```

### 5. Use Descriptive Variable Names

```javascript
// ✅ GOOD: Clear intent
const activeUsers = $input.all().filter(item => item.json.active);
const totalRevenue = activeUsers.reduce((sum, user) => sum + user.json.revenue, 0);

// ❌ BAD: Unclear purpose
const a = $input.all().filter(item => item.json.active);
const t = a.reduce((s, u) => s + u.json.revenue, 0);
```

### 6. Debug with console.log()

```javascript
// Debug statements appear in browser console
const items = $input.all();
console.log(`Processing ${items.length} items`);

for (const item of items) {
  console.log('Item data:', item.json);
  // Process...
}

return result;
```

---

## Troubleshooting

### Problem: The operator skipped the imported context and answered too generically

**Symptoms:** The result ignores the upstream workflow in `plugins/antigravity-awesome-skills/skills/n8n-code-javascript`, fails to mention provenance, or does not use any copied source files at all.
**Solution:** Re-open `metadata.json`, `ORIGIN.md`, and the most relevant copied upstream files. Check the `external_source` block first, then restate the provenance before continuing.

### Problem: The imported workflow feels incomplete during review

**Symptoms:** Reviewers can see the generated `SKILL.md`, but they cannot quickly tell which references, examples, or scripts matter for the current task.
**Solution:** Point at the exact copied references, examples, scripts, or assets that justify the path you took. If the gap is still real, record it in the PR instead of hiding it.

### Problem: The task drifted into a different specialization

**Symptoms:** The imported skill starts in the right place, but the work turns into debugging, architecture, design, security, or release orchestration that a native skill handles better.
**Solution:** Use the related skills section to hand off deliberately. Keep the imported provenance visible so the next skill inherits the right context instead of starting blind.

### Imported Troubleshooting Notes

#### Imported: Error Prevention - Top 5 Mistakes

### #1: Empty Code or Missing Return (Most Common)

```javascript
// ❌ WRONG: No return statement
const items = $input.all();
// ... processing code ...
// Forgot to return!

// ✅ CORRECT: Always return data
const items = $input.all();
// ... processing ...
return items.map(item => ({json: item.json}));
```

### #2: Expression Syntax Confusion

```javascript
// ❌ WRONG: Using n8n expression syntax in code
const value = "{{ $json.field }}";

// ✅ CORRECT: Use JavaScript template literals
const value = `${$json.field}`;

// ✅ CORRECT: Direct access
const value = $input.first().json.field;
```

### #3: Incorrect Return Wrapper

```javascript
// ❌ WRONG: Returning object instead of array
return {json: {result: 'success'}};

// ✅ CORRECT: Array wrapper required
return [{json: {result: 'success'}}];
```

### #4: Missing Null Checks

```javascript
// ❌ WRONG: Crashes if field doesn't exist
const value = item.json.user.email;

// ✅ CORRECT: Safe access with optional chaining
const value = item.json?.user?.email || 'no-email@example.com';

// ✅ CORRECT: Guard clause
if (!item.json.user) {
  return [];
}
const value = item.json.user.email;
```

### #5: Webhook Body Nesting

```javascript
// ❌ WRONG: Direct access to webhook data
const email = $json.email;

// ✅ CORRECT: Webhook data under .body
const email = $json.body.email;
```

**See**: ERROR_PATTERNS.md for comprehensive error guide

---

## Related Skills

- `@00-andruia-consultant` - Use when the work is better handled by that native specialization after this imported skill establishes context.
- `@00-andruia-consultant-v2` - Use when the work is better handled by that native specialization after this imported skill establishes context.
- `@10-andruia-skill-smith` - Use when the work is better handled by that native specialization after this imported skill establishes context.
- `@10-andruia-skill-smith-v2` - Use when the work is better handled by that native specialization after this imported skill establishes context.

## Additional Resources

Use this support matrix and the linked files below as the operator packet for this imported skill. They should reflect real copied source material, not generic scaffolding.

| Resource family | What it gives the reviewer | Example path |
| --- | --- | --- |
| `references` | copied reference notes, guides, or background material from upstream | `references/n/a` |
| `examples` | worked examples or reusable prompts copied from upstream | `examples/n/a` |
| `scripts` | upstream helper scripts that change execution or validation | `scripts/n/a` |
| `agents` | routing or delegation notes that are genuinely part of the imported package | `agents/n/a` |
| `assets` | supporting assets or schemas copied from the source package | `assets/n/a` |



### Imported Reference Notes

#### Imported: Quick Reference Checklist

Before deploying Code nodes, verify:

- [ ] **Code is not empty** - Must have meaningful logic
- [ ] **Return statement exists** - Must return array of objects
- [ ] **Proper return format** - Each item: `{json: {...}}`
- [ ] **Data access correct** - Using `$input.all()`, `$input.first()`, or `$input.item`
- [ ] **No n8n expressions** - Use JavaScript template literals: `` `${value}` ``
- [ ] **Error handling** - Guard clauses for null/undefined inputs
- [ ] **Webhook data** - Access via `.body` if from webhook
- [ ] **Mode selection** - "All Items" for most cases
- [ ] **Performance** - Prefer map/filter over manual loops
- [ ] **Output consistent** - All code paths return same structure

---

#### Imported: Additional Resources

### Related Files
- DATA_ACCESS.md - Comprehensive data access patterns
- COMMON_PATTERNS.md - 10 production-tested patterns
- ERROR_PATTERNS.md - Top 5 errors and solutions
- BUILTIN_FUNCTIONS.md - Complete built-in reference

### n8n Documentation
- Code Node Guide: https://docs.n8n.io/code/code-node/
- Built-in Methods: https://docs.n8n.io/code-examples/methods-variables-reference/
- Luxon Documentation: https://moment.github.io/luxon/

---

**Ready to write JavaScript in n8n Code nodes!** Start with simple transformations, use the error patterns guide to avoid common mistakes, and reference the pattern library for production-ready examples.

#### Imported: Data Access Patterns

### Pattern 1: $input.all() - Most Common

**Use when**: Processing arrays, batch operations, aggregations

```javascript
// Get all items from previous node
const allItems = $input.all();

// Filter, map, reduce as needed
const valid = allItems.filter(item => item.json.status === 'active');
const mapped = valid.map(item => ({
  json: {
    id: item.json.id,
    name: item.json.name
  }
}));

return mapped;
```

### Pattern 2: $input.first() - Very Common

**Use when**: Working with single objects, API responses, first-in-first-out

```javascript
// Get first item only
const firstItem = $input.first();
const data = firstItem.json;

return [{
  json: {
    result: processData(data),
    processedAt: new Date().toISOString()
  }
}];
```

### Pattern 3: $input.item - Each Item Mode Only

**Use when**: In "Run Once for Each Item" mode

```javascript
// Current item in loop (Each Item mode only)
const currentItem = $input.item;

return [{
  json: {
    ...currentItem.json,
    itemProcessed: true
  }
}];
```

### Pattern 4: $node - Reference Other Nodes

**Use when**: Need data from specific nodes in workflow

```javascript
// Get output from specific node
const webhookData = $node["Webhook"].json;
const httpData = $node["HTTP Request"].json;

return [{
  json: {
    combined: {
      webhook: webhookData,
      api: httpData
    }
  }
}];
```

**See**: DATA_ACCESS.md for comprehensive guide

---

#### Imported: Critical: Webhook Data Structure

**MOST COMMON MISTAKE**: Webhook data is nested under `.body`

```javascript
// ❌ WRONG - Will return undefined
const name = $json.name;
const email = $json.email;

// ✅ CORRECT - Webhook data is under .body
const name = $json.body.name;
const email = $json.body.email;

// Or with $input
const webhookData = $input.first().json.body;
const name = webhookData.name;
```

**Why**: Webhook node wraps all request data under `body` property. This includes POST data, query parameters, and JSON payloads.

**See**: DATA_ACCESS.md for full webhook structure details

---

#### Imported: Return Format Requirements

**CRITICAL RULE**: Always return array of objects with `json` property

### Correct Return Formats

```javascript
// ✅ Single result
return [{
  json: {
    field1: value1,
    field2: value2
  }
}];

// ✅ Multiple results
return [
  {json: {id: 1, data: 'first'}},
  {json: {id: 2, data: 'second'}}
];

// ✅ Transformed array
const transformed = $input.all()
  .filter(item => item.json.valid)
  .map(item => ({
    json: {
      id: item.json.id,
      processed: true
    }
  }));
return transformed;

// ✅ Empty result (when no data to return)
return [];

// ✅ Conditional return
if (shouldProcess) {
  return [{json: processedData}];
} else {
  return [];
}
```

### Incorrect Return Formats

```javascript
// ❌ WRONG: Object without array wrapper
return {
  json: {field: value}
};

// ❌ WRONG: Array without json wrapper
return [{field: value}];

// ❌ WRONG: Plain string
return "processed";

// ❌ WRONG: Raw data without mapping
return $input.all();  // Missing .map()

// ❌ WRONG: Incomplete structure
return [{data: value}];  // Should be {json: value}
```

**Why it matters**: Next nodes expect array format. Incorrect format causes workflow execution to fail.

**See**: ERROR_PATTERNS.md #3 for detailed error solutions

---

#### Imported: Common Patterns Overview

Based on production workflows, here are the most useful patterns:

### 1. Multi-Source Data Aggregation
Combine data from multiple APIs, webhooks, or nodes

```javascript
const allItems = $input.all();
const results = [];

for (const item of allItems) {
  const sourceName = item.json.name || 'Unknown';
  // Parse source-specific structure
  if (sourceName === 'API1' && item.json.data) {
    results.push({
      json: {
        title: item.json.data.title,
        source: 'API1'
      }
    });
  }
}

return results;
```

### 2. Filtering with Regex
Extract patterns, mentions, or keywords from text

```javascript
const pattern = /\b([A-Z]{2,5})\b/g;
const matches = {};

for (const item of $input.all()) {
  const text = item.json.text;
  const found = text.match(pattern);

  if (found) {
    found.forEach(match => {
      matches[match] = (matches[match] || 0) + 1;
    });
  }
}

return [{json: {matches}}];
```

### 3. Data Transformation & Enrichment
Map fields, normalize formats, add computed fields

```javascript
const items = $input.all();

return items.map(item => {
  const data = item.json;
  const nameParts = data.name.split(' ');

  return {
    json: {
      first_name: nameParts[0],
      last_name: nameParts.slice(1).join(' '),
      email: data.email,
      created_at: new Date().toISOString()
    }
  };
});
```

### 4. Top N Filtering & Ranking
Sort and limit results

```javascript
const items = $input.all();

const topItems = items
  .sort((a, b) => (b.json.score || 0) - (a.json.score || 0))
  .slice(0, 10);

return topItems.map(item => ({json: item.json}));
```

### 5. Aggregation & Reporting
Sum, count, group data

```javascript
const items = $input.all();
const total = items.reduce((sum, item) => sum + (item.json.amount || 0), 0);

return [{
  json: {
    total,
    count: items.length,
    average: total / items.length,
    timestamp: new Date().toISOString()
  }
}];
```

**See**: COMMON_PATTERNS.md for 10 detailed production patterns

---

#### Imported: Built-in Functions & Helpers

### $helpers.httpRequest()

Make HTTP requests from within code:

```javascript
const response = await $helpers.httpRequest({
  method: 'GET',
  url: 'https://api.example.com/data',
  headers: {
    'Authorization': 'Bearer token',
    'Content-Type': 'application/json'
  }
});

return [{json: {data: response}}];
```

### DateTime (Luxon)

Date and time operations:

```javascript
// Current time
const now = DateTime.now();

// Format dates
const formatted = now.toFormat('yyyy-MM-dd');
const iso = now.toISO();

// Date arithmetic
const tomorrow = now.plus({days: 1});
const lastWeek = now.minus({weeks: 1});

return [{
  json: {
    today: formatted,
    tomorrow: tomorrow.toFormat('yyyy-MM-dd')
  }
}];
```

### $jmespath()

Query JSON structures:

```javascript
const data = $input.first().json;

// Filter array
const adults = $jmespath(data, 'users[?age >= `18`]');

// Extract fields
const names = $jmespath(data, 'users[*].name');

return [{json: {adults, names}}];
```

**See**: BUILTIN_FUNCTIONS.md for complete reference

---

#### Imported: Integration with Other Skills

### Works With:

**n8n Expression Syntax**:
- Expressions use `{{ }}` syntax in other nodes
- Code nodes use JavaScript directly (no `{{ }}`)
- When to use expressions vs code

**n8n MCP Tools Expert**:
- How to find Code node: `search_nodes({query: "code"})`
- Get configuration help: `get_node_essentials("nodes-base.code")`
- Validate code: `validate_node_operation()`

**n8n Node Configuration**:
- Mode selection (All Items vs Each Item)
- Language selection (JavaScript vs Python)
- Understanding property dependencies

**n8n Workflow Patterns**:
- Code nodes in transformation step
- Webhook → Code → API pattern
- Error handling in workflows

**n8n Validation Expert**:
- Validate Code node configuration
- Handle validation errors
- Auto-fix common issues

---

#### Imported: Limitations

- Use this skill only when the task clearly matches the scope described above.
- Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
- Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.