VariableAssignment NodeTypeCode: variable-assignment

When to Use

• Initialize a counter at 0: Before entering a Loop node, assign processedCount = 0. Increment it inside the loop body using a subsequent VariableAssignment with ValueExpression = {{ $var.processedCount + 1 }}.
• Store the current UTC timestamp: Capture runStartedAt at the beginning of a batch workflow using a CodeExecute node to get new Date().toISOString(), then assign it via VariableAssignment. Reference it in final log entries to calculate total run duration.
• Capture a computed value for multiple uses: An HTTP call returns an API response with a deeply nested customer tier. Assign it once to customerTier and reference it in three downstream nodes — Switch, Email subject line, and database write — without re-fetching or re-navigating the nested path each time.
• Set a flag based on a condition: After an Approval node, assign isApproved = true on the approved port and isApproved = false on the rejected port. Downstream nodes branch on {{ $var.isApproved }} without needing to know the approval node's output structure.
• Save an ID from a previous node: A database insert returns a new record ID. Assign it to newInvoiceId immediately so multiple subsequent nodes — a PDF generator, an email sender, and an audit logger — can all reference the same ID consistently.

Configuration

Value Resolution Priority

When multiple sources are available, the node resolves the value in this order (first match wins):

1. InputData["value"] — if the preceding node explicitly passes a field named value in its output, that takes priority.
2. InputData["value_expression"] — if the preceding node passes a field named value_expression, it is evaluated as an expression.
3. Settings.Value — the constant value configured in the node settings.
4. Settings.ValueExpression — the expression configured in the node settings.

Output Ports

Output Fields

Sample Configurations

Constant value assignment

{
  "nodeType": "variable-assignment",
  "settings": {
    "VariableName": "processingStatus",
    "Value": "pending"
  }
}

Dynamic expression assignment

{
  "nodeType": "variable-assignment",
  "settings": {
    "VariableName": "customerId",
    "ValueExpression": "{{ $output.crmLookup.data.customer.id }}"
  }
}

Counter increment inside a loop

{
  "nodeType": "variable-assignment",
  "settings": {
    "VariableName": "processedCount",
    "ValueExpression": "{{ $var.processedCount + 1 }}"
  }
}

Sample Output

Success Port

{
  "assigned": {
    "orderTotal": 1250.00,
    "customerTier": "gold",
    "discountRate": 0.15,
    "processedDate": "2025-03-15",
    "isEligibleForShipping": true
  },
  "variableCount": 5,
  "_previousValues": {
    "orderTotal": null,
    "customerTier": null
  }
}

Expression Reference

Node Policies & GuardRails

Pattern Examples

Pattern 1 — Capture New Record ID for Multi-Node Reuse

A database insert returns the new invoice record ID. Multiple downstream nodes (PDF generator, email, audit log) all need this ID — assign it once and reference everywhere.

// VariableAssignment after DB insert node
{
  "VariableName": "newInvoiceId",
  "ValueExpression": "{{ $output.dbInsertNode.insertedId }}"
}

// Downstream PDF generator references: {{ $var.newInvoiceId }}
// Downstream email node references: "Invoice #{{ $var.newInvoiceId }} is attached"
// Downstream audit log references: {{ $var.newInvoiceId }}

Pattern 2 — Set Approval Flag on Decision Ports

After an Approval node, set a boolean flag on both the approved and rejected ports. Downstream nodes branch on the flag without coupling to the Approval node's output structure.

// On 'approved' port of Approval node:
{
  "VariableName": "approvalGranted",
  "Value": true
}

// On 'rejected' port of Approval node:
{
  "VariableName": "approvalGranted",
  "Value": false
}

// Downstream IfCondition — clean expression on the flag:
// Condition: {{ $var.approvalGranted }} === true

Pattern 3 — Running Total Accumulator in a Loop

A loop iterates over invoice line items. A VariableAssignment inside the loop accumulates the running total for use in a summary node after the loop completes.

// Before loop — initialize
{
  "VariableName": "invoiceTotal",
  "Value": 0
}

// Inside loop body — increment
{
  "VariableName": "invoiceTotal",
  "ValueExpression": "{{ $var.invoiceTotal + $output.currentItem.lineAmount }}"
}

// After loop — reference in email subject
// "Invoice total: {{ $var.invoiceTotal }}"