How to set invoice date in quickbooks invoice?

I am using quickbooks and I want to set the invoice date to what ever I want. I am using this code.

If I set it to TxnDate field it throws me error. So how can I set the invStartDate?

const createInvoiceObj = {
    DocNumber: docNumber,
    Line: [
      {
        Id: "1",
        LineNum: 1,
        Description: `The description`,
        Amount: 1232,
        DetailType: "SalesItemLineDetail",
        SalesItemLineDetail: {
          ItemRef: {
            value: "19",
            name: "Service"
          },
          UnitPrice: 1232,
          Qty: "1"
        }
      }
    ],
    CustomerRef: {
      value: "1"
    },
    CustomerMemo: {
      value: "Thank you for your business and have a great day!"
    },
    TotalAmt: totalAmount,
    TxnDate: moment(order.createdAt).format("YYYY-MM-DD")  // TxnDate: '2020-05-22'
  };

Error I am getting when using TxnDate

{
  "Fault": {
    "Error": [
      {
        "Message": "Transaction date is prior to start date for inventory item",
        "Detail": "Transactions with inventory (QOH) products cant be dated earlier than the Inventory Start Date for the product",
        "code": "6270",
        "element": ""
      }
    ],
    "type": "ValidationFault"
  },
  "time": "2020-05-27T05:26:58.217-07:00"
}

Solution

The correct field to set the date of the invoice is TxnDate.

Example:

{
  "Invoice": {
    "TxnDate": "2014-09-19", 
...

This is documented well here:

https://developer.intuit.com/app/developer/qbo/docs/api/accounting/all-entities/invoice#the-invoice-object

If you get this error message:

"Error": [
      {
        "Message": "Transaction date is prior to start date for inventory item",
        "Detail": "Transactions with inventory (QOH) products cant be dated earlier than the Inventory Start Date for the product",
        "code": "6270",
        "element": ""
      }
    ],

It means you're sending a date that makes no sense. In a real-world scenario, what you're trying to do is this:

You have 0 widgets in inventory 
You try to sell 5 items (you can't, you have zero items in inventory)
You start carrying and stocking widgets in inventory

The invoice date needs to be after the date you created/started carrying the item/product.

Change the date of the invoice so that the invoice is dated after you stated carrying the item/product.