Value not returning right - arrays

Question

I am having a issue getting my code to return the correct value.
I am building spreadsheet to help me with cooking for a video game I play. I am trying to track the amount of all the ingredients I have for cooking. I want to be able to update the amount I have from a dashboard rather than go scroll through the list to find each ingredient individually.
Here is what I have setup so far.
I have a page called Updater where I am selecting from a drop down a certain ingredient(cell A2). Next to that drop down is cell for me to enter a new amount of that ingredient that I have(cell B2).
The second page is called Ingredients. This has a 2 columns. Column 1 is a list of the ingredients and in column 2 is the number I currently have on hand.
The script I have written so far can find me the row number, but when I try to get the current amount I have for the ingredient to make sure the code is working, it doesnt return anything in the log.
There is my code
function finalTest(){
var spreadsheet = SpreadsheetApp.getActiveSpreadsheet();
var fs = spreadsheet.getSheetByName("Ingredients");
var ts = spreadsheet.getSheetByName("Updater");
var data = fs.getDataRange().getValues();
var luItem = ts.getRange("A2").getValue();
var newAmt = ts.getRange("B2").getValue();
var rn = 0;
Logger.log(rn);
Logger.log(newAmt);
Logger.log(data);
Logger.log(luItem);
for(var i = 0; i<data.length;i++){
if(data[i][0] == luItem){ //[1] because column B
Logger.log((i+1))
return i+1;
}
}
rn = i;
Logger.log(rn);
var fsr = fs.getRange(rn,2).getValue();
Logger.log(fsr);
}
Right now the logger will return up to where it logs "i", but will not return the new rn or fsr values.
Any help would be greatly appreciated.

Answer 1

A function immediately returns on the return statement. So you can only return one value there - or an object with multiple values inside.
As it looks that you just want to log data out, you would have to do that inside the if, but before the return to reach:
for (var i = 0; i < data.length; i++) {
if (data[i][0] == luItem) {
// first do all the logging
Logger.log(i + 1);
rn = i;
Logger.log(rn);
var fsr = fs.getRange(rn,2).getValue();
Logger.log(fsr);
// and then return from the function
return i + 1;
}
// what should be returned here??
}
Please also note that you should return a value or handle it somehow else when the loop runs through and the condition is never met.
If the return value then is still i + 1, you could make the if-condition instead part of the stop condition of the loop:
var i = 0;
for (; (i < data.length) && (data[i][0] == luItem); i++);
// no loop body needed here!
// do the logging outside the loop
Logger.log(i + 1);
rn = i;
Logger.log(rn);
var fsr = fs.getRange(rn,2).getValue();
Logger.log(fsr);
// and then return from the function
return i + 1;