JS: String.prototype.charAt
str.charAt(index)-
Return a string of length 1 that's the String Code Unit at index index of str.
"abc".charAt(0) === "a"
Return empty string if index is out of bound.
"abc".charAt(9) === ""
str.charAt(index)Return a string of length 1 that's the String Code Unit at index index of str.
"abc".charAt(0) === "a"
Return empty string if index is out of bound.
"abc".charAt(9) === ""