Google Apps Sheets if statement not executing - google-apps-script

Question

I've been working on a Google Sheets Script for my work, and have hit a road block. The goal here is to identify a cell in the heading row with a specific title and return the column it resides in. (Ie: in the heading row find "Email" in column "C" and return the number "3").
So far I've been able to find that the if statement isn't running. I'm pretty new to this language so any help would be greatly appreciated.
function findEmail(){
var searchString = "Email";
var data = sheet.getDataRange().getValues();
var row = 1;
var columnValues = sheet.getRange(row, 3, sheet.getLastRow()).getValues(); //1st is header row
var EMCol = columnValues.findIndex(searchString); //Row Index - 2\
var i;
for(i = 0; i<data.length;i++){
var j;
SpreadsheetApp.getActiveSheet().getRange('E2').setValue('Hello');
if(data[0][i] == EMCol){
SpreadsheetApp.getActiveSheet().getRange('E3').setValue('World');
// Logger.log((i+1))
// j = i+1
// return i+1;
}
return j;
};
}
This is what the sheet looks like after it has ran. As you can see nothing inside the if statement ran so there is no "World at E3.

Answer 1

When I run your code I get a TypeError, GAS doesn't have a findIndex() method. If you just want to find the column index then this function should do the job.
I'm not sure what you are trying to achieve with the Hello and World lines.
function findEmail() {
var searchString = "Email";
var data = sheet.getDataRange().getValues();
var columnIndex;
for (var i = 0; i < data[0].length; i++) {
if (data[0][i] == searchString) {
columnIndex = i + 1;
break;
}
}
Logger.log(columnIndex);
return columnIndex;
}