The getSublistValue & getSublistText return the internal Id of the item. I'm after the item name - what function is required?

var component_item_name = rec.getSublistText({
    sublistId: 'component',
    fieldId: 'item',
    line: x
});

will depend on the record, but the safe bet is usually to inspect the record in a debugger/console

Tried this in console and it too returned an internal ID:

require(['N/currentRecord'], function(currentRec){
	var rec = currentRec.get()
	console.log(rec.getSublistText("component","item", 0))
});

log the record, not your output

I tried using '*compitemname'* instead of 'item' but that just returned undefined. The compitemname has the text value I require

you may just have to deal with looking up the names

How do you mean?

do a search or query to lookup the names from the internal id

I see - I had that in mind but was hoping to avoid it. So I could build a saved search with all the items and do a lookup on the internal id and retrieve the item name.

ideally you filter it so you only get the items in your component sublist