JavaScript for...in Iteration

1// ForEach Array iteration method
2const arr = [
3  {key: 'k1', value: 'val1'},
4  {key: 'k2', value: 'val2'},
5  {key: 'k3', value: 'val3'}
6];
7
8arr.forEach(element => {
9  // console.log(element);    
10});
11
12// For...In Array elements iterations method
13for (let arrElem in arr) {
14  console.log(arr[arrElem])
15}
16
17// For...In String chars
18const str = 'xpto';
19for (let char in str) {
20  console.log(str[char])
21}
22
23
24// For...In Object properties iterations method
25const obj = {  
26  a: 1,
27  b: 2,
28  c: 3,
29  d: 4
30}
31
32for (let key in obj) {
33  // console.log(`${key} ${obj[key]}`)
34}