JS Practice — Built-in Objects

Object.keys() — counting and iterating

📖 Usage Example

// Get array of own enumerable property names
const obj = { a: 1, b: 2, c: 3 }
Object.keys(obj)   // → ['a', 'b', 'c']

Use Object.keys() to get an array of an object's own enumerable property names for iteration or counting.

Object.keys() — practical use

Object.keys() is commonly used for iterating over an object's properties or counting them.

Challenge: Implement countProperties(obj) that returns the number of own enumerable properties.

💡 Hints (1)