What is the purpose of the `Object.keys()` method?

Q: What is the purpose of the `Object.keys()` method?

const person = { name: "John", age: 30, job: "Developer" }; const keys = Object.keys(person); // Returns: ["name", "age", "job"]

Difficulty: 3/10

enumeration, property iteration, object introspection

The `Object.keys()` method is used to retrieve an array of the enumerable property names of an object. It provides a way to iterate through an object's properties.

Scenario Questions

0-2 years experience

1You have const user = {name: 'Alice', age: 30, active: true}. How would you get an array of its property names to render a simple list in the UI?
2Write a short snippet that uses Object.keys to sum all numeric values in an object representing a shopping cart.
3What would Object.keys(null) return, and how would you protect your code against that case?

2-5 years experience

Follow-up Questions

How does Object.keys differ from Object.getOwnPropertyNames?
Can you rely on the order of keys returned by Object.keys?
What happens if the argument to Object.keys is null or a primitive?