string to integer (atoi) javascript code example

Example: string to integer (atoi) javascript

/**
 * @param {string} str
 * @return {number}
 */
var myAtoi = function(str) {
  var i = 0;
  var sign = 1;
  var res = 0;
  var len = str.length;
  var INT_MAX = 2147483647;
  var INT_MIN = - INT_MAX - 1;

  while (str[i] === ' ') i++;

  if (str[i] === '+' || str[i] === '-') {
    sign = str[i] === '+' ? 1 : -1;
    i++;
  }

  while (str[i] >= '0' && str[i] <= '9') {
    res = (res * 10) + (str[i] - 0);
    if (sign === 1 && res > INT_MAX) return INT_MAX;
    if (sign === -1 && res > INT_MAX + 1) return INT_MIN;
    i++;
  }

  return res * sign;
};