items = _input.all()

return [
    {
        "json": {
            "id": item["json"].get("id"),
            "name": item["json"].get("name", "Unknown").upper(),
            "email": item["json"].get("email", "").lower(),
            "processed": True
        }
    }
    for item in items
]

items = _input.all()
total = sum(item["json"].get("amount", 0) for item in items)
valid_items = [item for item in items if item["json"].get("amount", 0) > 0]

return [{
    "json": {
        "total": total,
        "valid_count": len(valid_items),
        "all_count": len(items)
    }
}]

import re

items = _input.all()
email_pattern = r'\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b'

all_emails = []
for item in items:
    text = item["json"].get("text", "")
    emails = re.findall(email_pattern, text)
    all_emails.extend(emails)

# Remove duplicates
unique_emails = list(set(all_emails))

return [{
    "json": {
        "emails": unique_emails,
        "count": len(unique_emails)
    }
}]

items = _input.all()
validated = []

for item in items:
    data = item["json"]
    errors = []

    if not data.get("email") or "@" not in data.get("email", ""):
        errors.append("Invalid email")
    if not data.get("name") or not data.get("name", "").strip():
        errors.append("Name required")

    validated.append({
        "json": {
            **data,
            "name": data.get("name", "").strip(),
            "email": data.get("email", "").lower().strip(),
            "valid": len(errors) == 0,
            "errors": errors if errors else None
        }
    })

return validated

from statistics import mean, median, stdev

items = _input.all()
values = [item["json"].get("value", 0) for item in items if "value" in item["json"]]

if values:
    return [{
        "json": {
            "mean": mean(values),
            "median": median(values),
            "stdev": stdev(values) if len(values) > 1 else 0,
            "min": min(values),
            "max": max(values),
            "count": len(values)
        }
    }]
else:
    return [{"json": {"error": "No values found"}}]

import hashlib
import base64

items = _input.all()

return [
    {
        "json": {
            **item["json"],
            "id_hash": hashlib.sha256(
                str(item["json"].get("id", "")).encode()
            ).hexdigest()[:16],
            "name_encoded": base64.b64encode(
                item["json"].get("name", "").encode()
            ).decode()
        }
    }
    for item in items
]

import urllib.parse

items = _input.all()

return [
    {
        "json": {
            **item["json"],
            "api_url": "https://api.example.com/users?" + urllib.parse.urlencode({
                "id": item["json"].get("id"),
                "format": "json"
            })
        }
    }
    for item in items
]

# ❌ WRONG: ModuleNotFoundError
import requests
import pandas

# ✅ CORRECT: Use HTTP Request node before the Code node
# OR switch to JavaScript and use $helpers.httpRequest()

# ❌ WRONG: No return
items = _input.all()
# Processing...
# Forgot to return!

# ✅ CORRECT: Always return
items = _input.all()
# Processing...
return [{"json": item["json"]} for item in items]

# ❌ WRONG: dict without list
return {"json": {"result": "success"}}

# ✅ CORRECT: list with dict
return [{"json": {"result": "success"}}]

# ❌ WRONG: Direct access crashes if key is missing
name = _json["user"]["name"]  # KeyError if user or name doesn't exist

# ✅ CORRECT: Use .get() with safe chaining
name = _json.get("user", {}).get("name", "Unknown")

# ❌ WRONG: Webhook data is not at _json root
email = _json["email"]   # KeyError!

# ✅ CORRECT: Webhook data is under ["body"]
email = _json["body"]["email"]

# ✅ SAFER: .get() for safe access
email = _json.get("body", {}).get("email", "no-email")