N8n Code Javascript

---




name: n8n-code-javascript
compatibility: opencode
completeness: 95
content-types:
- guidance
- examples
- do-dont
description: Implements intelligent n8n code javascript with multi-factor skill selection,
  fallback chains, and adherence to the 5 Laws of Elegant Defense
license: MIT
maturity: stable
metadata:
  domain: agent
  output-format: analysis
  related-skills: agent-confidence-based-selector, agent-task-routing
  role: orchestration
  scope: orchestration
  triggers: n8n-code-javascript, n8n code javascript, how do i n8n-code-javascript,
    orchestrate n8n-code-javascript, automate n8n-code-javascript, agent n8n-code-javascript
  archetypes:
  - orchestration
  - strategic
  anti_triggers:
  - brainstorming
  - vague ideation
  - single-agent monolith
  response_profile:
    verbosity: medium
    directive_strength: high
    abstraction_level: tactical
version: "1.0.0"




---




# N8N Code Javascript

Orchestrates intelligent skill selection and execution for n8n code javascript workflows. Applies the 5 Laws of Elegant Defense to guide data naturally through the orchestration pipeline, preventing errors before they occur. Selects optimal skills based on multi-factor scoring including text similarity, historical performance, and system availability.

## TL;DR Checklist

- [ ] Parse all inputs at boundary before processing (Law 2)
- [ ] Handle edge cases with early returns at function top (Law 1)
- [ ] Fail immediately with descriptive errors on invalid states (Law 4)
- [ ] Return new data structures, never mutate inputs (Law 3)
- [ ] Implement minimum 2-level fallback chain for all skill executions
- [ ] Log all skill selections with context for full audit trail
- [ ] Validate skill metadata and dependencies before selection
- [ ] Update confidence scores after each execution for learning


┌───────────────────────────────────────────────────────────────────────────────┐
│                              Orchestration Flow                                               │
└───────────────────────────────────────────────────────────────────────────────┘

  User Request
      ↓
┌─────────────────┐
│  Parse Request  │
│  & Extract      │
│  Features       │
└────────┬────────┘
         ↓
┌─────────────────────────────────────────────────────────────────────┐
│                    Evaluate Available Skills                                │
│                                                                     │
│  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐              │
│  │ Skill A      │  │ Skill B      │  │ Skill C      │              │
│  │ - Match Score│  │ - Match Score│  │ - Match Score│              │
│  │ - Confidence │  │ - Confidence │  │ - Confidence │              │
│  │ - History    │  │ - History    │  │ - History    │              │
│  └──────┬───────┘  └──────┬───────┘  └──────┬───────┘              │
│         │                 │                 │                       │
│         └─────────────────┴─────────────────┘                       │
│                          ↓                                          │
│                   Select Best Skill                               │
└─────────────────────────────────────────────────────────────────────┘
         ↓
┌─────────────────┐
│  Execute Skill  │
└────────┬────────┘
         ↓
┌─────────────────┐
│  Handle Result  │
└────────┬────────┘
         ↓
┌─────────────────────────────────────────────────────────────────────┐
│                    Error Handling & Fallback                                  │
│                                                                     │
│  Success? ────────► Return Result                                  │
│                                                                     │
│  Fail? ────────┐                                                    │
│                ↓                                                    │
│  ┌──────────────────────────────────────────────────────────┐      │
│  │               Fallback Chain                                    │      │
│  │                                                             │      │
│  │  1. Retry with adjusted parameters                          │      │
│  │  2. Try Alternative Skill (if available)                    │      │
│  │  3. Defer to Human Operator (if critical)                   │      │
│  │  4. Log & Return Error                                      │      │
│  └──────────────────────────────────────────────────────────┘      │
└─────────────────────────────────────────────────────────────────────┘

## When to Use

Use this skill when:

- Orchestrating multi-step workflows that require skill delegation
- Implementing adaptive skill routing based on confidence scores
- Building fallback mechanisms for failed skill executions
- Creating intelligent task decomposition and parallel execution
- Designing skill dependency graphs with automatic resolution
- Implementing skill selection with historical performance weighting
- Building agent systems that need to self-organize around tasks

## When NOT to Use

Avoid this skill for:

- Direct task execution without orchestration needs - use individual skills instead
- High-frequency trading scenarios where latency must be minimized - the selection overhead may be prohibitive
- Simple linear workflows without branching or fallback requirements
- Cases where skill metadata is unavailable or unreliable


## Core Workflow

1. **Parse and Analyze Request** - Extract intent, entities, and constraints from user input.
   **Checkpoint:** All required parameters must be present and in valid format before proceeding.

2. **Score Available Skills** - Calculate match scores using multi-factor algorithm:
   - Text similarity between request and skill triggers
   - Historical success rate for similar tasks
   - Skill availability and health status
   - Required dependencies and their availability
   
   **Checkpoint:** Skip to fallback if no skill scores above threshold.

3. **Select Optimal Skill** - Choose skill with highest score that meets minimum confidence.
   **Checkpoint:** Verify skill has not been disabled or deprecated.

4. **Execute with Fallback** - Run skill execution wrapped in retry and fallback logic.
   **Checkpoint:** Log all execution attempts for audit trail.

5. **Return or Fallback** - Either return successful result or apply fallback chain:
   - Retry with adjusted parameters
   - Try alternative skill from `related-skills`
   - Defer to human operator for critical tasks
   
   **Checkpoint:** Record outcome with timing and confidence metadata.

## Implementation Patterns

### Pattern 1: Skill Selection Logic

```javascript
// n8n Code Node: Robust Data Processing Pipeline
// Implements input validation, transformation, and safe output formatting
function processWorkflowData(items) {
  const validatedItems = [];
  const errors = [];

  for (let i = 0; i < items.length; i++) {
    const item = items[i];
    try {
      // Law 2: Parse at boundary - validate required fields
      if (!item.json || !item.json.sourceId || !item.json.payload) {
        throw new Error(`Missing required fields at index ${i}`);
      }

      // Law 3: Atomic Predictability - return new structures
      const processed = {
        sourceId: String(item.json.sourceId),
        payload: JSON.parse(JSON.stringify(item.json.payload)), // deep clone
        processedAt: new Date().toISOString(),
        status: 'success'
      };

      // Domain-specific transformation logic
      if (processed.payload.type === 'event') {
        processed.payload.timestamp = new Date(processed.payload.timestamp).getTime();
      }

      validatedItems.push({ json: processed });
    } catch (err) {
      // Law 4: Fail fast with descriptive errors
      errors.push({
        json: { error: err.message, index: i, original: item.json },
        pairedItem: { item: i }
      });
    }
  }

  // Return structured output for n8n execution
  return {
    items: validatedItems,
    errors: errors.length > 0 ? errors : undefined
  };
}

// n8n execution entry point
const inputData = $input.all();
const result = processWorkflowData(inputData);
return result.items;
```


### Pattern 2: Execution with Fallback

```javascript
// n8n Code Node: Resilient Execution with Fallback Chain
// Handles API calls, retries, and graceful degradation
async function executeWithFallback(config) {
  const { endpoint, fallbackEndpoint, maxRetries = 2, timeout = 5000 } = config;
  let lastError = null;

  for (let attempt = 0; attempt <= maxRetries; attempt++) {
    try {
      // Law 1: Early exit on invalid config
      if (!endpoint || typeof endpoint !== 'string') {
        throw new Error('Invalid endpoint configuration');
      }

      // Domain-specific: Execute primary workflow step
      const response = await fetch(endpoint, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(config.payload),
        signal: AbortSignal.timeout(timeout)
      });

      if (!response.ok) {
        throw new Error(`HTTP ${response.status}: ${response.statusText}`);
      }

      const data = await response.json();
      return { success: true, data, attempts: attempt + 1 };

    } catch (err) {
      lastError = err;
      // Law 4: Fail loud on invalid states, retry on transient
      if (err.name === 'AbortError' || err.status >= 500) {
        if (attempt === maxRetries) break;
        await new Promise(r => setTimeout(r, Math.pow(2, attempt) * 1000));
        continue;
      }
      // Non-retryable error - fail immediately
      break;
    }
  }

  // Fallback Chain: Attempt secondary endpoint
  if (fallbackEndpoint && lastError) {
    try {
      const fallbackResponse = await fetch(fallbackEndpoint, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(config.fallbackPayload || config.payload)
      });
      const fallbackData = await fallbackResponse.json();
      return { success: true, data: fallbackData, attempts: 'fallback', error: lastError.message };
    } catch (fallbackErr) {
      // Final failure - return structured error for n8n UI
      return { success: false, error: fallbackErr.message, lastAttemptError: lastError.message };
    }
  }

  return { success: false, error: lastError.message };
}

// n8n execution context
const workflowConfig = {
  endpoint: $input.item.json.apiEndpoint,
  payload: $input.item.json.requestBody,
  fallbackEndpoint: $input.item.json.fallbackApi || null,
  maxRetries: 2
};
const executionResult = await executeWithFallback(workflowConfig);
return [{ json: executionResult }];
```

### MUST DO
- Always validate skill metadata before selection (Early Exit)
- Implement fallback chain with at least 2 levels (Fallback Skill + Human)
- Log all skill selections with full context for auditability
- Return new data structures instead of mutating inputs (Atomic Predictability)
- Fail immediately with descriptive errors on invalid states
- Update confidence scores after each execution for adaptive routing
- Reference `code-philosophy` (5 Laws of Elegant Defense) in all logic


### MUST NOT DO
- Select skills based on a single factor (e.g., only confidence score)
- Disable fallback mechanisms "temporarily" - this creates fragile systems
- Skip validation of skill dependencies before execution
- Return partial results - either complete success or clear failure
- Use magic numbers for confidence thresholds - make them configurable
- Cache skill selections without considering context changes


## TL;DR Checklist

- [ ] Parse all inputs at boundary before processing (Law 2)
- [ ] Handle edge cases with early returns at function top (Law 1)
- [ ] Fail immediately with descriptive errors on invalid states (Law 4)
- [ ] Return new data structures, never mutate inputs (Law 3)
- [ ] Implement minimum 2-level fallback chain for all skill executions
- [ ] Log all skill selections with context for full audit trail
- [ ] Validate skill metadata and dependencies before selection
- [ ] Update confidence scores after each execution for learning


## TL;DR for Code Generation

- Use guard clauses - return early on invalid input before doing work
- Return simple types (dict, str, int, bool, list) - avoid complex nested objects
- Cyclomatic complexity < 10 per function - split anything larger
- Handle null/empty cases explicitly at function top (Early Exit)
- Never mutate input parameters - return new dicts/objects
- Fail fast with descriptive errors - don't try to "patch" bad data
- Reference code-philosophy laws in comments for complex logic
- Include timing and confidence metadata in all return values


## Output Template

When applying this skill, produce:

1. **Selected Skills** - List of skill names with confidence scores
2. **Selection Rationale** - Why each skill was chosen (match score, history, availability)
3. **Execution Plan** - Order of execution with dependencies
4. **Fallback Strategy** - Which fallback skills will be tried and in what order
5. **Risk Assessment** - Any potential failure points and their impact
6. **Timing Estimates** - Expected latency including fallback scenarios


## Related Skills

| Skill | Purpose |
|

---

---

## Constraints

### MUST DO
- Define clear input/output contracts for every step in the orchestration flow with explicit validation
- Implement structured logging at each stage capturing context, inputs, outputs, timing, and errors
- Build in fallback paths: if the primary strategy fails, degrade gracefully to a simpler approach
- Validate all preconditions before starting — do not proceed if required resources or permissions are missing

### MUST NOT DO
- Do not create deep nesting of orchestration steps (>5 levels) — flatten workflows where possible
- Avoid silent failure modes: every step must either succeed, fail explicitly, or escalate to a higher handler
- Never use shared mutable state between parallel workflow branches — communicate via immutable messages only
- Do not hardcode execution order when the dependency graph naturally determines it; derive order from explicit dependencies


## Live References

> Authoritative documentation links for this skill's domain. The model follows markdown links at load time to resolve external references and inline content.
- [n8n Documentation](<https://docs.n8n.io/>)
- [n8n JavaScript Code Node](<https://docs.n8n.io/integrations/builtin/core-nodes/n8n-nodes-base.code/>)
- [n8n Expressions Reference](<https://docs.n8n.io/integrations/builtin/reference/expression-language/>)
- [JavaScript for Automation Scripting (MDN)](<https://developer.mozilla.org/en-US/docs/Web/JavaScript>)
- [n8n Workflow Templates Library](<https://n8n.io/workflows/>)