How to Reliably Identify Line Index in NetSuite Using lineuniquekey

Overview

In NetSuite scripting, retrieving the correct line index from a sublist like item is essential — especially when working with Map/Reduce, User Event, or Client Scripts that manipulate specific lines.

When records are edited and lines are inserted or deleted, the line numbers may shift, making them unreliable over time. Instead of relying on the line number from a saved search, the lineuniquekey should be used for accurate line identification.

❌ Problem with Using line Field from Search Results

When a saved search returns the line field:

• It may return values like 1, 2...
• These numbers do not remain consistent when a user inserts a new line in between.
• The order is not guaranteed, and referencing line by index can lead to updating the wrong line.

✅ Recommended Approach: Use lineuniquekey

lineuniquekey is a stable and unique identifier for each line, regardless of its position.

🔧 Sample Code Snippet

Here’s how to use lineuniquekey to find the correct line:

let lineIndex = poRec.findSublistLineWithValue({
    sublistId: 'item',
    fieldId: 'lineuniquekey',
    value: lineUniqueKeyValue  // value from your search result
});

Once you have lineIndex, you can safely select and update the line:

if (lineIndex !== -1) {
    poRec.selectLine({ sublistId: 'item', line: lineIndex });
    poRec.setCurrentSublistValue({
        sublistId: 'item',
        fieldId: 'custcol_example_field',
        value: someValue
    });
    poRec.commitLine({ sublistId: 'item' });
}