How do you move logic from Google Sheet formula to Javascript?

Question

I have a function yahoofinance which queries Yahoo.Finance for stock data based on a stock ticker, Before I can call the function. I need to do some modifications to the input.

Tickers in my sheet are of the form [venue].[company] , for example XNAS.GOOG (Google at Nasdaq), XAMS.INGA (ING Bank at Amsterdam) and XSWX.CRSP (Crispr at Swiss Exchange).

The codes that I use for the venues are international, but most API's don't use these same codes. For instance, the Amsterdam stock exchange officially is XAMS , but AMS on Google API and AS on Yahoo. So I have a sheet called Exchanges with all these venues listed. When calling my custom yahoofinance function, it takes the standard 'XMAS.INGA' as input, then cuts off the venue ( XAMS ) and looks up the Yahoo name ( AS ), then passes INGA.AS to the Yahoo API:

=yahoofinance(index(split(A2, "."), 0, 2) & "." & vlookup(index(split(A2, "."), 0, 1), Exchanges!E:J, 6, false))

function yahoofinance(ticker) {
  // send ticker to Yahoo API
}

The logic, which is now in cell B2 in the sheet, is getting complicated to follow. I would like to move it, if possible, into the function and pass only the ticker from A2 :

=yahoofinance(A2)

function yahoofinance(ticker) {
    const venue = ticker.split();
    // etc

    // end up with INGA.AS, and pass to Yahoo API
}

My question is: is it possible to move the logic that is now in my sheet, into the function? For example, if and how can I perform the same vlookup from within yahoofinance ? Is it even possible?

I am planning to really extend the functionality of yahoofinance , perhaps even rework it to a generic finance function which also takes as argument to which API you want to pass a ticker: =yahoofinance(ticker, api) , so any help to get me started with a solid basis here is greatly appreciated.

Answer 1

You can try this custom formula to get the modified value:

Script:

function yahoofinance(ticker) {
  var [venue, company] = ticker.split("\.");
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Exchanges');
  var lastRow = sheet.getLastRow();
  // get Exchanges!E:J values
  var mapping = sheet.getRange(1, 5, lastRow, 6).getValues();
  // lookup equivalent, filter then get 6th column and append to company
  var modifiedTicker = company + '.' + mapping.filter(row => row[0] == venue).flat()[5];
  // you now have the modified ticker. Use it on your function.
  // ...
  return modifiedTicker;
}

B7 formula:

=index(split(A2, "."), 0, 2) & "." & vlookup(index(split(A2, "."), 0, 1), Exchanges!E:J, 6, false)

Output: