JAVASCRIPT

for in

    for (key in object) {
      console.log(key,object[key]);
    }

for in loop

//basic for in loop
const car = {
  carName: "Ford",
  carDoor: 4,
  carSpeed: 180
}

for (objKey in car) {
  console.log(car[objKey])
}
//output 
Ford
4
180

loop for in

let list = ["a", "b", "c"];
// for in
for (let i in list) {
	// i is index
	console.log(i);   // "0", "1", "2",
	console.log(list[i]);   // "a", "b", "c"
}
// for of
for (let i of list) {
	// i is value
	console.log(i);   // "a", "b", "c"
}

For-in loop

const obj = {
  a: 1,
  b: 2,
  c: 3,
};

// Long-hand
const keys = Object.keys(obj);
for (let i = 0; i < keys.length; i++) {
  const key = keys[i];
  const value = obj[key];
  // ...
}

// Short-hand
for (const key in obj) {
  const value = obj[key];
  // ...
}