Determine if a string is numeric in Office Scripts

Question

How do I determine if a string is numeric in Office Scripts if the string cannot have any letters in it? For example, 'a1234' should not be a number. The Number methods like parsefloat, parseInt, IsInteger, and isNan don't help because they accept strings that have any numbers in them when wrapped in Number (Number(value) or +value) or don't accept strings.

Answer 1

I show that when the string 'a1234' is passed into Number.IsInteger(), the value is false:

function main(workbook: ExcelScript.Workbook){
  let str: string = "a1234"
  console.log(Number.isInteger(str)) //false
}

Is this what you were expecting? If not, what were you expecting? Or what are you trying to achieve?