Nodejs Utililty Methods String Empty Check

String.prototype.isBlank = function() {
    if (this.trim().length == 0)
        return true;
    else
        return false;
};
Date.prototype.toLocalDate = function() {
    var localTime = this.getTime();
    var localOffset = this.getTimezoneOffset() * 60000;
...

String.prototype.isBlank = function() {
    if (this == undefined || this == "" || this == null || /^\s*$/.test(this)) {
        return true;
    return false;
};

String.prototype.isBlank = function()
  try
    var value = this.toString().trim();
    if (value == null) return true;
      if (value.length == 0)
        return true;
      else
...

String.prototype.isBlank = function(pattern) {
  return /^\s*$/.test(this);
};