How Can I Efficiently Get an Array of Keys from a JavaScript Object?

Retrieving Keys from an Object as an Array

In JavaScript, extracting the keys of an object into an array can be achieved through various methods. While the provided code snippet using a for-in loop is functional, it may not be the most concise or efficient approach.

Using Object.keys()

A less verbose and more modern method is to utilize the built-in Object.keys() function. This function directly returns an array containing the object's keys. The following code demonstrates its usage:

const foo = {
  alpha: 'puffin',
  beta: 'beagle',
};

const keys = Object.keys(foo);
console.log(keys); // ['alpha', 'beta']

In this example, the keys of the 'foo' object are retrieved as an array stored in the 'keys' variable. Object.keys() operates in O(n) time, where 'n' represents the number of properties in the object.

Compatibility Considerations

Object.keys() is widely supported in modern browsers and Node.js environments. However, for older browsers or environments lacking this function, a polyfill can be used.

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