How to Resolve SSS_MISSING_REQD_ARGUMENT for Item Pricing Sublists

The internal ID for each currency pricing list is structured by concatenating the base 'price' ID with the currency's internal ID. For example, the internal ID for the USA currency (internal ID 1) would result in 'price1'. Earlier SuiteScript examples might have demonstrated accessing these lists as follows:

javascript
priceID = "price";
var internalId = nlapiSearchRecord('currency', null, new nlobjSearchFilter(
'symbol',
        null,'contains', currencyID))[0].getId();
priceID = priceID + internalId;
// ...
itemRecord.selectLineItem(priceID, 1);
itemRecord.setCurrentLineItemMatrixValue(priceID, 'price', 1, basePrice);
itemRecord.commitLineItem(priceID);

However, when attempting to dynamically construct the sublistId in SuiteScript 2.0 using the + operator, as shown below:

javascript
var priceID = "price";
var currency = salesOrderRecord.getValue({
 fieldId: 'currency'
});
priceID = priceID + currency;
// ...
var itemCount = itemRecord.getLineCount({
 sublistId: priceID
});

This can lead to an SSS_MISSING_REQD_ARGUMENT error:

json
"name":"SSS_MISSING_REQD_ARGUMENT",
"message":"DeferredDynamicRecord.getLineCount: Missing a required argument: sublistId"

In this specific context, it was found that using the concat() function instead of the + assignment operator for the pricing list ID resolved the issue.

The corrected approach for constructing the sublistId is:

javascript
priceID.concat(currency)

This ensures the sublistId is correctly passed to SuiteScript functions.