for in loop javascript

1var colors=["red","blue","green"];
2for (let i = 0; i < colors.length; i++) { 
3  console.log(colors[i]);
4}

1var person = {"name":"taylor","age":31};
2for (property in person) {
3	console.log(property,person[property]);
4}
5//name taylor
6//age 31

1var subjects = {
2	'math': 85,
3	'physics': 75,
4}
5
6for (var i in subjects) {
7	console.log(i + ' : ' + subjects[i]);
8}
9
10// math : 85
11// physics : 75

1let array = [1,2,3,4,5,6,7,8,9,10]; 
2// our array that we will use the for loop on
3for (let i = 0; i < array.length; i++) { 
4  // this loop will console log the element at array[i] starting at 0
5  // and will continue looping for i < array.length 
6  console.log(array[i]);
7  // after each loop i will increase by 1
8}
9
10// this will console log
11// 1
12// 2
13// 3
14// 4
15// 5
16// 6
17// 7
18// 8
19// 9
20// 10
21

1
2let arry = {
3    name: "Rakibul Islam",
4    class: "Tane",
5    grup: "A",
6    roll: 10,
7    sub: "Arse"
8}
9//for in loop used to object
10for(let i in arry){
11    console.log(i,arry[i]);
12}

1function diagonalDifference(arr) {
2    // Write your code here
3    // return (arr); 11,2,4,4,5,6,10,8,-12
4    let n = arr.length;
5    let pri,sec = 0;
6
7    pri = sec = 0; //initialize both diagonal sum to 0
8    for (let i= 0; i < n; i++) {
9        //console.log( "PRI(arr)= ", i,i);
10        //console.log( arr[i][i]);
11        //console.log( "SEC(arr)= ", i,n-i-1);
12        //console.log( arr[i][n-i-1]);
13        pri += arr[i][i];
14        sec += arr[i][n - i - 1]; 
15    }
16	
17  	// return |x| is the absolute value of x
18    if(pri==sec){
19        return (0);
20    }else {
21        if (pri>sec){
22            return (pri-sec);
23        }else{
24            return (sec-pri);
25        }
26    }
27}