How Can I Get a List of JavaScript Object Properties?

Listing Properties of a JavaScript Object

In JavaScript, there are several approaches to obtain a list of properties associated with an object.

Using Object.keys Method:

The Object.keys() method is available in modern browsers and provides a concise and efficient way to retrieve property names. For instance:

var myObject = { "ircEvent": "PRIVMSG", "method": "newURI", "regex": "^http://.*" };
var keys = Object.keys(myObject);

Polyfill for Object.keys:

If you need to support older browsers, you can use a polyfill for Object.keys:

var getKeys = function(obj) {
  var keys = [];
  for (var key in obj) {
    keys.push(key);
  }
  return keys;
};

Custom Prototype Method:

You can also extend the Object prototype to add the keys() method:

Object.prototype.keys = function() {
  var keys = [];
  for (var key in this) {
    keys.push(key);
  }
  return keys;
};

This allows you to call .keys() on any object:

myObject.keys(); // Returns ["ircEvent", "method", "regex"]

Each of these methods returns an array containing the property names of the object.

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