Adding string with dot-notation as a key to JavaScript objects

dot-notation-object.js

// Be careful when changing Object's prototype to avoid overwriting of methods
if (Object.prototype.setPath === undefined && Object.prototype.getPath === undefined) {
    
  Object.prototype.setPath = function (path, value, notation) {
    function isObject(obj) { return (Object.prototype.toString.call(obj) === '[object Object]' && !!obj);}
    notation = notation || '.';
    path.split(notation).reduce(function (prev, cur, idx, arr) {
      var isLast = (idx === arr.length - 1);
      // if <cur> is last part of path
      if (isLast) return (prev[cur] = value);
      // if <cur> is not last part of path, then returns object if existing value is object or empty object
      return (isObject(prev[cur])) ? prev[cur] : (prev[cur] = {});
    }, this);
    return this;
  };
    
  Object.prototype.getPath = function(path, notation) {
    notation = notation || '.';
    return path.split(notation).reduce(function(prev, cur) {
      return (prev !== undefined) ? prev[cur] : undefined;
    }, this);
  };
    
}

// how to use
var config = {};
config.setPath('db.common.credentials', {login: 'root', pass: ''});
config.setPath('db.host.dev', 'localhost');
config.setPath('db|host|prod', 'prodhost', '|');
console.log(config.getPath('db.host'));