I created two different variables a and b and in first for loop, I placed a.push and then a.unshift and in second for loop, I placed b.unshift first and then b.push but why the both variables (a and b) output will be same as [10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
let a = [];
for(let i=0 ; i <=10 ; i++) {
a.push(i);
a.unshift(i);
}
console.log(a);
let b = [];
for(let j=0 ; j <=10 ; j++) {
b.unshift(j);
b.push(j);
}
console.log(b);
The push() method adds one or more elements to the end of an array and returns the new length of the array.
The unshift() method adds one or more elements to the beginning of an array and returns the new length of the array.
First one always works on the end, second one on the beginning. So it doesn't matter if you call first unshift() or push() because they do the same action every time. It's like adding. It doesn't matter if you do 3 + 5 or 5 + 3. Theoretically, it do the same in the opposite order, but because it uses the same value the result is the same.
Try
let a = [];
for(let i=0 ; i <=10 ; i++) {
a.push(i + 1);
a.unshift(i);
}
console.log(a);
let b = [];
for(let j=0 ; j <=10 ; j++) {
b.unshift(j + 1);
b.push(j);
}
console.log(b);
The result is different.
