$input Directive | BizFirst Expression Evaluation

Property	Value
Directive name	`input`
Required isolation level	Safe
Project	`NodeData.Services`
Data source	`INodeExecutionData.CurrentItem` / `.InputItems`

Selectors

Selector	Resolves to
`$input.current`	The currently active execution item (the item this node is processing)
`$input.first`	First item in the input collection
`$input.last`	Last item in the input collection
`$input.items`	All input items as a JSON array
`$input.current._binary.fieldName`	Binary/file attachment on the current item

Path Reference

// Input item structure (example):
{
  "id": 1001,
  "email": "alice@acme.com",
  "firstName": "Alice",
  "amount": 4500.00,
  "status": "pending",
  "address": {
    "city": "Dublin",
    "country": "IE"
  },
  "tags": ["vip", "enterprise"],
  "_binary": {
    "attachment": { "filename": "invoice.pdf", "mimeType": "application/pdf", "data": "base64..." }
  }
}

// Expressions:
{@ $input.current.id }                       → 1001
{@ $input.current.email }                    → "alice@acme.com"
{@ $input.current.address.city }             → "Dublin"
{@ $input.current.tags[0] }                  → "vip"
{@ $input.current._binary.attachment @json } → binary descriptor as JSON
{@ $input.first.id }                         → first item's id
{@ $input.items @json }                      → full array serialized

Complex Scenarios

Scenario 1 — Forward All Input Fields to External API

Send the full current item as the body of an HTTP request:

HTTP Request body

{@ $input.current @json }

Entire input item serialized as JSON request body

Scenario 2 — Build a Notification from Input + Context

Slack message

🔔 New {@ $input.current.type @uppercase } from {@ $input.current.email } — Amount: {@ $input.current.amount } {@ $ctx.tenant.currency } | Ref: {@ $input.current.referenceId @default:N/A }

🔔 New INVOICE from alice@acme.com — Amount: 4500 EUR | Ref: INV-2024-001

Scenario 3 — Conditional Processing Based on Input Field

// Switch node: route by payment method
{@ $input.current.paymentMethod @uppercase }
// → "CARD" → routes to Stripe branch
// → "BANK_TRANSFER" → routes to SEPA branch
// → "PAYPAL" → routes to PayPal branch

Scenario 4 — Batch Processing: Read from First Item for Configuration

When processing a batch, the first item contains batch metadata used by all subsequent items:

// All items in the batch share the same batchId (in first item)
{@ $input.first.batchId }
// Used in: audit log, error reporting, deduplication

{@ $input.first.tenantOverride @default:{@ $ctx.tenant.id } }
// Falls back to context tenant if first item doesn't specify an override

Scenario 5 — Binary Attachment Processing

// HTTP node: upload the attached PDF to a document store
// Body: binary data as base64
{@ $input.current._binary.attachment @base64 }

// Header: Content-Type from binary descriptor
{@ $js`return context.input.current._binary.attachment.mimeType` }

// Filename for storage path
{@ $js`return context.input.current._binary.attachment.filename` }

Scenario 6 — Array Field Extraction for Batch Insert

Input contains an array field; extract specific elements for downstream processing:

// Input: { "orderId": "ORD-001", "items": [{sku:"A",qty:2},{sku:"B",qty:5}] }

// First SKU in the items array
{@ $input.current.items[0].sku }  → "A"

// Total quantity across all items (JavaScript needed for aggregation)
{@ $js`
return context.input.current.items.reduce((sum, i) => sum + i.qty, 0)
` }  → 7

// Serialize the items array for API body
{@ $js`return JSON.stringify(context.input.current.items)` }

Common Errors

Error	Cause	Fix
`PathNotFound: current.fieldName`	Field doesn't exist on this item type	Use `@default` or check field name with trace logging
`PathNotFound: first`	Empty input collection	Add an upstream guard to verify non-empty before entering the node
Returns wrong item	Using `current` outside of a loop (no active item)	Use `first` when the node processes one batch, not per-item

$input — Node Input Directive