let arr = [1,2,3,4,"hello",6];
for (let a of arr) {
    console.log(a);
}

• not limited to arrays. Also looping through objects possible!
• for arrays you can also use the forEach() method (see "Iterator: .forEach()")

myObject = {
    name: "arthur",
    age: 78
}

// loop through object and display all property names and values
for (let props in myObject) {
  console.log(`${props}: ${myObject[props]}`)
};
// outputs:   
//   name: arthur  
//   age: 78