cellToTitleCase

function cellToTitleCase() {
    function titleCase(str) {
    let upper = true
    let newStr = ""
    for (let i = 0, l = str.length; i < l; i++) {
        if (str[i] == " ") {
            upper = true
            newStr += str[i]
            continue
        }
        newStr += upper ? str[i].toUpperCase() : str[i].toLowerCase()
        upper = false
    }
    return newStr
  }
      let spreadsheet = SpreadsheetApp.getActive();
      let sheet = spreadsheet.getActiveSheet();
      let cellRange = sheet.getActiveCell();
      let currentValue =  cellRange.getValue()
      let titleCaseValue = titleCase(currentValue)
      cellRange.setValue(titleCaseValue)
  
}