Hey Everyone i want to get these info from the header Discount Item Rate and add them as line item Script :

/**
 * @NApiVersion 2.x
 * @NScriptType UserEventScript
 */
define(['N/record'], function(record) {

  function beforeSubmit(context) {
    if (context.type === context.UserEventType.CREATE || context.type === context.UserEventType.EDIT) {
      var newRecord = context.newRecord;

      var discountItemId = newRecord.getValue({
        fieldId: 'discountitem'
      });

      var discountRate = newRecord.getValue({
        fieldId: 'rate'
      });

      if (discountItemId && !isDiscountSublistItem(newRecord, discountItemId)) {
        try {
          var lineCount = newRecord.getLineCount({
            sublistId: 'item'
          });

          newRecord.selectNewLine({
            sublistId: 'item'
          });

          newRecord.setCurrentSublistValue({
            sublistId: 'item',
            fieldId: 'item',
            value: discountItemId
          });

          newRecord.setCurrentSublistValue({
            sublistId: 'item',
            fieldId: 'rate',
            value: discountRate
          });

          newRecord.setCurrentSublistValue({
            sublistId: 'item',
            fieldId: 'amount',
            value: 0
          });

          newRecord.commitLine({
            sublistId: 'item'
          });
        } catch (e) {
          log.error('Error : ', e);
        }
      }
    }
  }

  function isDiscountSublistItem(record, discountItemId) {
    var lineCount = record.getLineCount({
      sublistId: 'item'
    });

    for (var i = 0; i < lineCount; i++) {
      var item = record.getSublistValue({
        sublistId: 'item',
        fieldId: 'item',
        line: i
      });

      if (item === discountItemId) {
        return true;
      }
    }

    return false;
  }

  return {
    beforeSubmit: beforeSubmit
  };
});

this script is not working onCreate and Edit as well

Are you trying to add the discount item if it doesn't already exist on the lines?

@Nathan L Yes exaclty and once done i want to set the header = null

I mean the code looks good to me for adding the line. I don't see anything in there for clearing out the fields in the header though. Is it just not adding your line? can you log something inside your if block to make sure its hitting that point in the code

you need to nail down your problem beyond not working