How to sync Google Sheets rows to a single QuickBooks Invoice (with negative lines) without complex loops

Hi ​@Samuel Oliver 👋

That's a great way to handle it! We'd love it if you could share an example of the JavaScript code you're using for that here so that others can try it in their Zap workflows as well. And I'd be happy to drop a link to that example code on the original closed topic so it's easier for anyone who comes across that one to find their way here.

Hi ​@SamB ! Thanks for reaching out. I would absolutely love it if you could link
this back to the original topic—hopefully, it saves some folks a few hours of
troubleshooting!

For anyone looking to implement this via a Code by Zapier (JavaScript) step,
here is a simplified version of the logic we use to split positive line items
and negative discounts into the specific formats the QuickBooks API requires.

When you pass your Google Sheets rows into this step as a JSON array (via
inputData.rawItems), the script iterates through them and shapes the
QBO-compliant payload:

// Parse the incoming array of Google Sheet rows
const items = JSON.parse(inputData.rawItems || "[]");

let qboLineItems = [];

items.forEach(item => {
let amount = parseFloat(item.amount);

if (amount >= 0) {
// 1. Structure standard positive line items
qboLineItems.push({
"Amount": amount,
"DetailType": "SalesItemLineDetail",
"SalesItemLineDetail": {
"ItemRef": {
"value": item.productId // Mapped from your QBO Product Library
},
"Qty": item.qty,
"UnitPrice": item.unitPrice
},
"Description": item.description
});
} else {
// 2. Structure negative line items (Discounts/Credits)
// Note: QBO requires the amount to be passed as an absolute value here
qboLineItems.push({
"Amount": Math.abs(amount),
"DetailType": "DiscountLineDetail",
"DiscountLineDetail": {
"DiscountAccountRef": {
"value": item.discountAccountId
}
},
"Description": "Applied Discount/Credit from Sheets"
});
}
});

// Output the formatted array to push into a Custom Request (POST) module
output = [{ formattedLineItems: qboLineItems }];

Note for builders: You will then map formattedLineItems directly into the "Data"
field of a Zapier Webhooks (Custom Request - POST) action pointing to the
/sales/Invoice endpoint.

Let me know if anyone needs help mapping their specific Sheet variables to the
input data!