Zie619/n8n-workflows · error · Error

Invalid quantity: ${input["Quantity Received"]}

Error message

Invalid quantity: ${input["Quantity Received"]}

What it means

Thrown by 'Calculate Total Price' when the webhook field `Quantity Received` cannot be parsed to a number. The getNumber helper strips non-numeric characters, runs parseFloat, and returns null for undefined/null/empty/NaN - the throw then reports the raw value.

Source

Thrown at workflows/Code/0926_Code_Webhook_Create_Webhook.json:800

          "mode": "list",
          "value": "1q0S6AVK7uxZG8sUQkpcZr01KToHPjOZ0gG3zKHLR6lw",
          "cachedResultUrl": "{{ $env.WEBHOOK_URL }}",
          "cachedResultName": "Plumbee Raw Material Delivery  (Responses)"
        }
      },
      "typeVersion": 4.5,
      "notes": "This googleSheets node performs automated tasks as part of the workflow."
    },
    {
      "id": "21c17077-9f9a-489a-b6a5-ea7a70a85cee",
      "name": "Calculate Total Price",
      "type": "n8n-nodes-base.code",
      "position": [
        6340,
        2040
      ],
      "parameters": {
        "jsCode": "// Get the input data\nconst input = $input.all()[0].json;\n\n// Debug: Log the entire input to see all available fields\nconsole.log(\"Complete Input Data:\", JSON.stringify(input, null, 2));\n\n// Improved number parser that handles different formats\nconst getNumber = (value) => {\n  if (value === undefined || value === null || value === \"\") return null;\n  \n  // Remove any currency symbols, commas, or extra spaces\n  const cleaned = String(value)\n    .replace(/[^\\d.-]/g, '')\n    .trim();\n    \n  const num = parseFloat(cleaned);\n  return isNaN(num) ? null : num;\n};\n\n// Use EXACT field names from your webhook payload\nconst quantity = getNumber(input[\"Quantity Received\"]);  // Not \"Quantity Received\"\nconst unitPrice = getNumber(input[\"Unit Price\"]);    // Not \"Unit Price\"\n\n// Validate\nif (quantity === null) throw new Error(`Invalid quantity: ${input[\"Quantity Received\"]}`);\nif (unitPrice === null) throw new Error(`Invalid price: ${input[\"Unit Price\"]}`);\n\n// Calculate total\nconst totalPrice = quantity * unitPrice;\n\n// Return results\n// Return clean output without debug info\nreturn {\n  json: {\n    \"Timestamp\": new Date().toISOString(),\n    \"Product ID\": input[\"Product ID\"],\n    \"Supplier Name\": input[\"Supplier Name\"],\n    \"Material Name\": input[\"Material Name\"],\n    \"Quantity Received\": quantity,\n    \"Description\": input[\"Description\"] || \"\",\n    \"Measurement Unit\": input[\"Measurement Unit\"],\n    \"Unit Price\": unitPrice,\n    \"Total Price\": totalPrice.toFixed(2),\n    \"Date of Delivery\": input[\"Date of Delivery\"],\n    \"Received By\": input[\"Received By\"],\n    \"Submission ID\": input[\"Submission ID\"]\n  }\n};"
      },
      "typeVersion": 2,
      "notes": "This code node performs automated tasks as part of the workflow."
    },
    {
      "id": "4ce817b0-2283-438f-82c7-6f4901fffdd3",
      "name": "Calculate Updated Current Stock",
      "type": "n8n-nodes-base.code",
      "position": [
        7640,
        1840
      ],
      "parameters": {
        "mode": "runOnceForEachItem",
        "jsCode": "const existingStock = parseFloat(\n$('Lookup Existing Stock').first().json['Current Stock']\n|| 0);\nconst newQuantity = parseFloat(\n  $('Validate Quantity Received').first().json['Quantity Received']);\nconst updatedStock = existingStock + newQuantity;\n\n\n  \nreturn {\n  json: {\n    ...$json,\n    \"Updated Current Stock\": updatedStock\n  }\n};"
      },
      "typeVersion": 2,
      "notes": "This code node performs automated tasks as part of the workflow."

View on GitHub (pinned to 94007c1445)

Solutions

  1. Make Quantity Received required and numeric at the form layer (input type=number, min>0).
  2. Check the exact field name in the arriving payload via the console.log of complete input data already present in the node.
  3. Trim units: extend the cleaner to also strip letters, or send machine-formatted values from the form.
  4. If zero-quantity submissions are invalid too, change the check to quantity === null || quantity <= 0.

Example fix

// before
const quantity = getNumber(input["Quantity Received"]);
if (quantity === null) throw new Error(`Invalid quantity: ${input["Quantity Received"]}`);

// after
const quantity = getNumber(input["Quantity Received"]);
if (quantity === null || quantity <= 0) {
  throw new Error(`Invalid quantity: ${JSON.stringify(input["Quantity Received"])} (field names present: ${Object.keys(input).join(', ')})`);
}
Defensive patterns

Strategy: validation

Validate before calling

const qtyRaw = input['Quantity Received'];
const qtyNum = Number(String(qtyRaw ?? '').replace(/[^\d.-]/g, ''));
if (!Number.isFinite(qtyNum) || qtyNum <= 0) {
  throw new Error(`Invalid quantity: ${JSON.stringify(qtyRaw)} (keys: ${Object.keys(input).join(', ')})`);
}

Type guard

const isValidQuantity = (v) => {
  if (v === undefined || v === null || v === '') return false;
  const n = parseFloat(String(v).replace(/[^\d.-]/g, ''));
  return Number.isFinite(n) && n > 0;
};

Prevention

When it happens

Trigger: Webhook form submitted with Quantity Received missing, empty string, or a value like 'abc' or ' pieces' that strips to nothing; field name mismatch (form sends 'quantity_received' or 'Qty Received'); value 0 is NOT rejected (parseFloat('0')=0 passes), so this specifically means unparseable input.

Common situations: Google Form / front-end form field renamed or made optional; respondents typing free text into a numeric field; leading/trailing currency or unit words in the value; webhook payload schema drift.

Related errors

AI-assisted analysis of Zie619/n8n-workflows@94007c1445 (2026-08-15). Data as JSON: /api/errors/e3a03c59041f43d0. Report an issue: GitHub.