How to Get All Keys of Object in JavaScript Quickly

Use Object.keys(yourObject) to get an array of all enumerable property names (keys) of an object in JavaScript. This method returns only the object's own keys, not inherited ones.

Syntax

The Object.keys() method takes one argument, the object you want to get keys from, and returns an array of strings representing the object's own enumerable property names.

• Object.keys(obj): Returns an array of keys from obj.

javascript

const keys = Object.keys(obj);

Example

This example shows how to get all keys from a simple object and print them.

javascript

const person = {
  name: "Alice",
  age: 30,
  city: "Wonderland"
};

const keys = Object.keys(person);
console.log(keys);

Output

["name", "age", "city"]

Common Pitfalls

One common mistake is expecting Object.keys() to return keys from the object's prototype chain. It only returns the object's own keys. Also, it returns only enumerable keys, so non-enumerable properties are skipped.

Another pitfall is using for...in loops without filtering, which includes inherited keys.

javascript

const parent = { inheritedKey: 1 };
const child = Object.create(parent);
child.ownKey = 2;

// Wrong: includes inherited keys
for (const key in child) {
  console.log(key); // outputs 'ownKey' and 'inheritedKey'
}

// Right: only own keys
console.log(Object.keys(child)); // outputs ['ownKey']

Output

ownKey
inheritedKey
["ownKey"]

Quick Reference

Summary tips for getting object keys:

• Use Object.keys(obj) for own enumerable keys.
• Use Object.getOwnPropertyNames(obj) to include non-enumerable keys.
• Use for...in with hasOwnProperty() check to avoid inherited keys.

Key Takeaways

Use Object.keys(obj) to get an array of an object's own enumerable keys.

Object.keys() does not include inherited or non-enumerable keys.

Avoid using for...in loops without filtering to prevent inherited keys from appearing.

For non-enumerable keys, use Object.getOwnPropertyNames(obj).

Always check if keys are own properties when iterating over objects.