for-in-loop.md

JavaScript For...In Loop

The for...in loop in JavaScript is used to iterate over the properties of an object. It is particularly useful when you want to loop through the keys (property names) of an object.

Syntax

for (variable in object) {
  // code to be executed
}

variable: A variable that will be assigned the property name on each iteration.
object: The object whose enumerable properties are iterated.

Note

The for...in loop iterates over enumerable properties, including inherited ones.
It is recommended to use caution when using for...in with arrays, as it may iterate over array methods and not just array elements.

Example

// Sample object
const car = {
  make: 'Toyota',
  model: 'Camry',
  year: 2022
};

// Using for...in loop to iterate over object properties
for (let key in car) {
  console.log(key + ': ' + car[key]);
}