JAVASCRIPT

for of vs for in javascript

let list = [4, 5, 6];

for (let i in list) {
   console.log(i); // "0", "1", "2",
}

for (let i of list) {
   console.log(i); // "4", "5", "6"
}

// EXAMPLE 2
let pets = new Set(["Cat", "Dog", "Hamster"]);
pets["species"] = "mammals";

for (let pet in pets) {
   console.log(pet); // "species"
}

for (let pet of pets) {
    console.log(pet); // "Cat", "Dog", "Hamster"
}

javascript for loops in vs of

let myArray = ["a", "b", "c"];

// for...in iterates over properties (like index)
for (let i in myArray){
  console.log(i); // → 0, 1, 2
} 

// for...of iterates over values
for (let i of myArray){
  console.log(i); // → a, b, c
}