JSFiddle - React, Tailwind, and code Playground
JavaScript
var aSheets = ['sheet1', 'sheet2', 'sheet3', 'sheet1'];
var sheetIndex = 1;
var sSheetName = '';
if (aSheets.indexOf('sheet1') !== -1) {
while (aSheets.indexOf('sheet1') !== -1) {
sheetIndex++;
sSheetName = ' - ' + sheetIndex;
}
}
console.log(sSheetName);