for..in
, which should not be confused with for..of
, can be used to iterate over the enumerable properties of an object:
const dog = { name: 'Roger', color: 'gray' }
for (let property in dog) {
console.log(property) // 'name' in the first iteration
// 'color' in the second
console.log(dog[property]) // 'Roger' in the first iteration
// 'gray' in the second
}
Since arrays are a special kind of object, we can iterate over the items in an array too:
const dogs = ['Roger', 'Vanille']
for (let index in dogs) {
console.log(dogs[index])
}
Lessons in this unit:
0: | Introduction |
1: | The `for` loop |
2: | The `do-while` loop |
3: | The `while` loop |
4: | The `for-of` loop |
5: | ▶︎ The `for-in` loop |
6: | Other kinds of loops |
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