Different Between for...in and for...of loops in Javascript

The for...of and for...in in Javascript have different behaviors. Here I will show the difference when looping through an array:

const datas = [1, 3, 5, 8, 9, 10]

for (const data of datas) {
    console.log(data) // Output: 1, 3, 5, 8, 9, 10
}

for (const data in datas) {
    console.log(data) // Output: 0, 1, 2, 3, 4, 5
}

From the example above, we can conclude that when using for...of, we will loop through the array values. Whereas when using for...in, we will loop through the array indexes.