pub fn comma(val: &str, args: Vec<&str>) -> Result<String, TransformerError>
Expand description

Insert commas to the given string in provided positions

    assert_eq!(comma("1234", vec!["3"])?, "1,234");
    assert_eq!(comma("1234567", vec!["3"])?, "1,234,567");
    assert_eq!(comma("1234567", vec!["3", "2"])?, "12,34,567");
    assert_eq!(comma("91234567", vec!["3", "2"])?, "9,12,34,567");