N/currentRecord Module
CurrentRecord.getSublistField()
Method Description: Returns a field object from a sublist. Use Record.getCurrentSublistField(options) if you are working with the current and non-committed line.
Returns: currentRecord.Field
Supported Script Types: Client scripts For more information, see SuiteScript 2.0 Client Script Type.
Governance: None
Module: N/currentRecord Module
Since: 2016.2
Search NetSuite - https://system.netsuite.com/app/help/helpcenter.nl?search=CurrentRecord.getSublistField(options)

// Code Example 1

//Add additional code

//...

var objField = objRecord.getSublistField({

    sublistId: 'item',

    fieldId: 'item',

    line: 3

});

//...

//Add additional code



//SOURCE: https://system.netsuite.com/app/help/helpcenter.nl?fid=section_4637583684.html