why am I getting a "TypeError: Cannot read property 'getLineCount' of undefined" on a beforeSubmit UE script triggered on a Journal Entry record - netsuite

Question

I am unsure how to troubleshoot or what this error means in NetSuites SuiteScript. There I am getting after I hit save on a journal entry is.:
"TypeError: Cannot read property 'getLineCount' of undefined [at Object.beforeSubmit (/SuiteScripts/Set Line Employee ADP ID.js:15:30)]"
I believe the error is with my getLineCount() function on line 15.
Functional Scenario: I am writing a script to populate a custom column field on a Journal entry line from a field on the customer record that is selected in the native entity field on the Journal Entry line.
Context: my script is triggering before submit on create or update of a Journal Entry
Here is my script:
`define (['N/record','N/runtime','N/search','N/log'],(rec,runtime,search,log)=> {
// Logic Of the before submit actions of the script:
function beforeSubmit(context){
//Find how many lines are in this JE
let jeLineNums = context.rec.getLineCount({
sublistId:'line'
});
//log the JE line numbers as a test
log.debug({
title: 'JE lines',
details: jeLineNums
});
// Loop through every line in the Journal Entry
for (let i = 0; i < jeLineNums; i++){
// Find the customer record ID of the customer on the line and store it
let customerid = context.rec.getSublistValue({
sublistId: 'line',
fieldId: 'entity_display',
line: i
});
// Then create a SS with the customer id as a criteria
let customerSearch = search.create({
type: "customer",
filters:
[
["entityid","is",customerid]
],
columns:
[
search.createColumn({
name: "custentity2",
label: "ADP ID"}),
],
});
// Run that ss and Store the ADP ID result into a vairable
function RunSearch(searchVar) {
return searchVar.run()
};
};
RunSearch(customerSearch).each(function(result){
var adpID = result.getValue({
name:'custentity2',
});
return false;
});
//log the JE line numbers as a test
log.debug({
title: 'CustomerADP ID',
details: adpId
});
// Set the Line Employee ADP ID field value to the ADP ID vairable stored
context.rec.setSublistValue({
sublistId: "line",
fieldId: "custcol_mhi_line_adp_id",
line: i,
value: adpId,
});
//End of the loop
};
return {
beforeSubmit: beforeSubmit,
};
});`

Answer 1

For SS2.1, you can do the following:
let { newRecord } = context;
//Find how many lines are in this JE
let jeLineNums = newRecord.getLineCount({
sublistId:'line'
});
Alternatively, for SS2.0:
//Find how many lines are in this JE
var jeLineNums = context.newRecord.getLineCount({
sublistId:'line'
});
"TypeError: Cannot read property 'getLineCount' of undefined [at
Object.beforeSubmit (/SuiteScripts/Set Line Employee ADP
ID.js:15:30)]"
The reason you're getting the error above is because you're trying to read an undefined property from context. The context object doesn't have a rec property. See more details here: beforeSubmit(context)