Google Sheets - Script to Change Currency Formatting Based On Dropdown Selection ($ + €) - google-apps-script

Question

I have a Sheet with two tabs — Tab 1 is a quote/invoice and Tab 2 is a list of clients. C3 on Tab 1 contains a dropdown list which pulls from Tab 2, Clients 1-4 use USD ($) but Client 5 uses EURO (€). Tab 1 also contains a costs column in I and a feeder column in H.
My goal is to use a script to change the currency formatting in column I based on what's selected in C3. When Client 5 is selected all costs in I need to contain a '€' prefix, and when anyone else is selected they need to contain a '$' prefix.
In the following code 'H' is a feeder cell where 'EURO' or 'literally anything else' can be entered to change the currency format in 'I' between '€' to '$':
function onEdit(e){
var sheetName = "Main Sheet";
var currencyCol = 8; //column H
var amountCol = 9; //column I
var defaultFormat = "[$$]#,##0.00";
var currencyFormat = {"USD":"[$$]#,##0.00",
"EURO":"[$€]#,##0.00"};
var r = e.range;
if(e.source.getSheetName()==sheetName && r.getColumn() == currencyCol){ // This assumes I want to manually change H, I'd rather have it automatically change between EURO (including € in column I) when client 5 is selected, and USD (including $ in column I) when clients 1-4 are selected
var uf = currencyFormat[r.getValue()];
uf = uf?uf:defaultFormat;
r.offset(0,amountCol-currencyCol).setNumberFormat(uf);
}
}
It works, but I have to manually type 'EURO' or 'anything else' in 'H' line-by-line to change the currencies for 'I' - but I need it to change automatically based on the selection in C3.
I tried using =if(C3="Client 5", "EURO", "") in Column H which works the first time Client 5 is selected in the dropdown, but doesn't reset 'I' to '$' once changed and needs to be manually typed in before working again.
I also tried 2 Macros which manually input 'EURO' and 'USD' into column H and tried to run them with a script to trigger when Client 5 is selected. It worked in 'H', but 'I' didn't change when the words appeared I think the issue is that the code isn't/can't trigger outside of manual data entry.
Any help would be great, I'm a beginner and I can't wrap my head around it. Feel free to message me or ask for a link to a test sheet.
Also I attached a screenshot of what tab 1 & 2 look like. I manually changed EURO to USD on Tab 1 to set that currency in column I, ideally that change can be based off C3Spreadsheet example

Answer 1

I believe your goal is as follows.
When a dropdown list of "C3" of "Tab1" sheet is changed, you want to change the number format of the cells "I8:I".
You want to retrieve the values of the dropdown list and the corresponding number formats from the cells "B4:C8" of "Tab2".
In this case, how about the following modification?
Modified script:
function onEdit(e) {
var sheetName1 = "Tab1"; // Please set the sheet name of "Tab1".
var sheetName2 = "Tab2"; // Please set the sheet name of "Tab2".
var r = e.range;
if (e.source.getSheetName() == sheetName1 && r.getA1Notation() == "C3") {
var defaultFormat = "[$$]#,##0.00";
var currencyFormat = { "DOLLAR": "[$$]#,##0.00", "EURO": "[$€]#,##0.00" };
var obj = e.source.getSheetByName(sheetName2).getRange("B2:C8").getValues().reduce((o, [b, c]) => (o[b] = c, o), {});
var sheet = r.getSheet();
sheet.getRange("I8:I" + sheet.getLastRow()).setNumberFormat(currencyFormat[obj[e.value]] || defaultFormat);
}
}
Note:
In this modified script, when the dropdown list of "C3" of "Tab1" sheet is changed, the number format of cells "I8:I" is changed by the values of "B4:C8" of "Tab2". In this case, the column "H" is not used. Please be careful about this.
In your script, "USD":"[$$]#,##0.00" and "EURO":"[$€]#,##0.00" are used. But, in your image, "DOLLAR" and "EURO" are used. In this modification, "DOLLAR" and "EURO" are used. Please be careful about this.
Reference:
reduce()