how to skip substring in javascript number code example

Example 1: javascript remove first character from string

let str = " hello";
str = str.substring(1);

Example 2: javascript remove first character from string

let str = 's';

str = (function f(s) { // don't use on large strings
  		return s.length<=1?'':f(s.slice(0, -1))+s[s.length-1]
	})(str); // ""