Excel Javascript (Office.js) - LastRow/LastColumn - better alternative? - excel

Question

I have been a fervent reader of StackOverflow over the last few years, and I was able to resolve pretty much everything in VBA Excel with a search and some adapting. I never felt the need to post any questions before, so I do apologize if this somehow duplicates something else, or there is an answer to this already and I couldn't find it.
Now I`m considering Excel-JS in order to create an AddIn (or more), but have to say that Javascript is not exactly my bread and butter. Over the time of using VBA, I find that one of the most simple and common needs is to get the last row in a sheet or given range, and maybe less often the last column.
I've managed to put some code together in Javascript to get similar functionality, and as it is... it works. There are 2 reasons I`m posting this
Looking to improve the code, and my knowledge
Maybe someone else can make use of the code meanwhile
So... in order to get my lastrow/lastcolumn, I use global variables:
var globalLastRow = 0; //Get the last row in used range
var globalLastCol = 0; //Get the last column in used range
Populate the global variables with the function to return lastrow/lastcolumn:
function lastRC(wsName) {
return Excel.run(function (context) {
var wsTarget = context.workbook.worksheets.getItem(wsName);
//Get last row/column from used range
var uRange = wsTarget.getUsedRange();
uRange.load(['rowCount', 'columnCount']);
return context.sync()
.then(function () {
globalLastRow = uRange.rowCount;
globalLastCol = uRange.columnCount;
});
});
}
And lastly get the value where I need them in other functions:
var lRow = 0; var lCol = 0;
await lastRC("randomSheetName");
lRow = globalLastRow; lCol = globalLastCol;
I`m mainly interested if I can return the values directly from the function lastRC (and how...), rather than go around with this solution.
Any suggestions are greatly appreciated (ideally if they don't come with stones attached).
EDIT:
I've gave up on using an extra function for this as for now, given that it uses extra context.sync, and as I've read since this post, the less syncs, the better.
Also, the method above is only good, as long your usedrange starts in cell "A1" (or well, in the first row/column at least), otherwise a row/column count is not exactly helpful, when you need the index.
Luckily, there is another method to get the last row/column:
var uRowsIndex = ws.getCell(0, 0).getEntireColumn().getUsedRange().getLastCell().load(['rowIndex']);
var uColsIndex = ws.getCell(0, 0).getEntireRow().getUsedRange().getLastCell().load(['columnIndex']);
To break down one of this examples, you are:
starting at cell "A1" getCell(0, 0)
select the entire column "A:A" getEntireColumn()
select the usedrange in that column getUsedRange() (i.e.: "A1:A12")
select the last cell in the used range getLastCell() (i.e.: "A12")
load the row index load(['rowIndex']) (for "A12" rowIndex = 11)
If your data is constant, and you don't need to check lastrow at specific column (or last column at specific row), then the shorter version of the above is:
uIndex = ws.getUsedRange().getLastCell().load(['rowIndex', 'columnIndex']);
Lastly, keep in mind that usedrange will consider formatting as well, not just values, so if you have formatted rows under your data, expect the unexpected.
late edit - you can specify if you want your used range to be of values only (thanks Ethan):
getUsedRange(valuesOnly?: boolean): Excel.Range;
I have to say a big thank you to Michael Zlatkovsky who has put a lot of work, in a lot of documentation, which I`m far from finishing to read.