n8n EXPRESSION SYNTAX — THE COMPLETE REFERENCE
===============================================================

  BASIC ACCESS:
  ├── Current node data: {{ $json.field_name }}
  ├── Specific node: {{ $node["NodeName"].json.field_name }}
  ├── Parameters: {{ $node["NodeName"].parameter.param_name }}
  └── Environment: {{ $env.MY_VARIABLE }}

  DATA NAVIGATION:
  ├── Nested object: {{ $json.address.city }}
  ├── Array element: {{ $json.items[0].name }}
  ├── Array length: {{ $json.items.length }}
  └── Optional chain: {{ $json.address?.city ?? "Unknown" }}

  WORKFLOW CONTEXT:
  ├── Execution ID: {{ $execution.id }}
  ├── Workflow name: {{ $workflow.name }}
  ├── Current date: {{ new Date().toISOString() }}
  ├── PKT timestamp: {{ new Date().toLocaleString('en-PK',
  │   {timeZone: 'Asia/Karachi'}) }}
  └── Item index: {{ $itemIndex }}

  WHERE EXPRESSIONS WORK:
  ├── Set node → field values
  ├── IF node → conditions
  ├── HTTP Request → URL, headers, body
  ├── Gmail → subject, body, to address
  ├── Google Sheets → column values
  └── Basically everywhere you see the {{ }} icon

===============================================================

// UNIVERSAL PAKISTANI PHONE NORMALIZER
// Use in a Code node for reliability

for (const item of $input.all()) {
  let phone = String(item.json.phone || '');

  // Step 1: Remove all non-digit characters
  phone = phone.replace(/[^0-9]/g, '');

  // Step 2: Handle different starting patterns
  if (phone.startsWith('92') && phone.length === 12) {
    phone = '+' + phone;                    // 923001234567 -> +923001234567
  } else if (phone.startsWith('0') && phone.length === 11) {
    phone = '+92' + phone.substring(1);     // 03001234567 -> +923001234567
  } else if (phone.length === 10 && phone.startsWith('3')) {
    phone = '+92' + phone;                  // 3001234567 -> +923001234567
  } else {
    phone = 'INVALID: ' + item.json.phone;  // Flag for manual review
  }

  item.json.phone_normalized = phone;
  item.json.phone_valid = !phone.startsWith('INVALID');
}
return $input.all();

PHONE FORMAT CONVERSION TABLE
===============================================================

  INPUT FORMAT          ->  OUTPUT (E.164)     STATUS
  ────────────────────────────────────────────────────
  03001234567           ->  +923001234567      Valid
  +923001234567         ->  +923001234567      Valid
  0300-123-4567         ->  +923001234567      Valid
  92300 1234567         ->  +923001234567      Valid
  300 1234567           ->  +923001234567      Valid
  923001234567          ->  +923001234567      Valid
  1234567               ->  INVALID            Flagged
  +1-555-123-4567       ->  INVALID            Flagged

  WHY THIS MATTERS:
  ├── WATI API requires +92XXXXXXXXXX format exactly
  ├── One wrong digit = failed WhatsApp message
  ├── Failed message = missed customer notification
  ├── Missed notification = unhappy client = lost retainer
  └── This one Code node prevents all of that

===============================================================

// Clean and format names from messy form submissions
for (const item of $input.all()) {
  let name = String(item.json.name || '');

  // Trim whitespace, collapse multiple spaces
  name = name.trim().replace(/\s+/g, ' ');

  // Convert to Title Case
  name = name.toLowerCase().replace(/\b\w/g, c => c.toUpperCase());

  item.json.name_clean = name;

  // Split into first/last for email personalization
  const parts = name.split(' ');
  item.json.first_name = parts[0] || '';
  item.json.last_name = parts.slice(1).join(' ') || '';
}
return $input.all();

// Expression in Set node (no Code node needed):
// Priority label based on score
{{ $json.score >= 80 ? "HOT"
   : $json.score >= 60 ? "WARM"
   : "COLD" }}

// Urgency flag for WhatsApp alert
{{ $json.score >= 80 ? "CALL IMMEDIATELY"
   : $json.score >= 60 ? "Follow up within 24 hours"
   : "Add to nurture list" }}

// PKR formatting
{{ "PKR " + Number($json.amount).toLocaleString('en-PK') }}
// Input: 45000 -> Output: "PKR 45,000"

// Extract company domain for enrichment
{{ $json.email.split('@')[1] }}
// ahmed@techstartup.pk -> techstartup.pk

// Extract domain from URL (Code node for reliability)
for (const item of $input.all()) {
  let url = String(item.json.website || '');
  url = url.replace(/^https?:\/\//, '')  // Remove protocol
           .replace(/^www\./, '')         // Remove www
           .split('/')[0]                 // Remove path
           .split(':')[0]                 // Remove port
           .toLowerCase();               // Normalize case
  item.json.domain = url;
}
return $input.all();

n8n DATA TYPES — WHEN EACH APPLIES
===============================================================

  JSON DATA (Text, Numbers, Objects):
  ├── Webhook payloads
  ├── API responses
  ├── Google Sheets data
  ├── AI-generated text
  ├── Form submissions
  └── Access via: {{ $json.field_name }}

  BINARY DATA (Files, Images, PDFs):
  ├── Email attachments
  ├── Downloaded files (HTTP Request)
  ├── Generated PDFs/images
  ├── Uploaded files
  └── Access via: {{ $binary.data }} or {{ $binary.attachment }}

  COMMON MISTAKE:
  ├── You generate a PDF report via an AI/Code node
  ├── You try to attach it to Gmail using {{ $json.report }}
  ├── Gmail sends an empty email — no attachment
  ├── WHY: The PDF is binary data, not JSON
  ├── FIX: Use {{ $binary.data }} in the Gmail attachment field
  └── Or use the "Move Binary Data" node to convert

  CONVERSION NODES:
  ├── "Move Binary Data" — converts between JSON and binary
  ├── "Read Binary File" — reads file from disk as binary
  ├── "Write Binary File" — saves binary to disk
  └── "Spreadsheet File" — converts CSV/Excel to JSON rows

===============================================================

// Current PKT timestamp (expression)
{{ new Date().toLocaleString('en-PK', {timeZone: 'Asia/Karachi'}) }}

// Is it business hours in Pakistan? (Code node)
for (const item of $input.all()) {
  const pktHour = new Date().toLocaleString('en-US', {
    timeZone: 'Asia/Karachi',
    hour: 'numeric',
    hour12: false
  });
  const hour = parseInt(pktHour);
  item.json.is_business_hours = (hour >= 9 && hour < 18);
  item.json.pkt_hour = hour;

  // Route: business hours -> immediate action, after hours -> queue
  item.json.action = item.json.is_business_hours
    ? "Send WhatsApp now"
    : "Queue for 9 AM PKT tomorrow";
}
return $input.all();

// Simple expression for amounts
{{ "PKR " + Number($json.amount).toLocaleString('en-PK') }}
// 1500000 -> "PKR 1,500,000"

// Code node with GST calculation
for (const item of $input.all()) {
  const amount = Number(item.json.amount);
  const gst = amount * 0.17;  // Pakistan GST rate: 17%
  item.json.subtotal = `PKR ${amount.toLocaleString('en-PK')}`;
  item.json.gst = `PKR ${gst.toLocaleString('en-PK')}`;
  item.json.total = `PKR ${(amount + gst).toLocaleString('en-PK')}`;
  item.json.total_raw = amount + gst;
}
return $input.all();

// Process all line items from a Shopify order
for (const item of $input.all()) {
  const lineItems = item.json.line_items || [];

  item.json.product_summary = lineItems
    .map(li => `${li.name} x${li.quantity}`)
    .join(', ');

  item.json.total_quantity = lineItems
    .reduce((sum, li) => sum + li.quantity, 0);

  item.json.item_count = lineItems.length;
}
return $input.all();
// Input: [{name:"Blue Kurta", quantity:2}, {name:"White Shalwar", quantity:1}]
// Output: product_summary = "Blue Kurta x2, White Shalwar x1"
//         total_quantity = 3
//         item_count = 2