I want to reverse an array without using the built-in methods but the following function is not working:
function reverseArray(arr) {
let brandNewArray = [];
for (let i = arr.length - 1; i >= 0; i--) {
brandNewArray += arr[i];
}
return brandNewArray;
}
reverseArray([1,2,3]);
Use push function instead of +=.
function reverseArray(arr) {
let brandNewArray = [];
for (let i = arr.length - 1; i >= 0; i--) {
brandNewArray.push(arr[i]);
}
return brandNewArray;
}
console.log(reverseArray([1,2,3]));Instead of += you need to push items into it. Using += at first time will assign to the brandNewArray a string, (as [] + 1 will give you "1"), with value of the last item. Then string concatenation goes and you got 321 as the final value of brandNewArray instead of array.
function reverseArray(arr) {
let brandNewArray = [];
for (let i = arr.length - 1; i >= 0; i--) {
brandNewArray.push(arr[i]);
}
return brandNewArray;
}
console.log(reverseArray([1,2,3]))const reverseArray = arr => arr.reduce((acc, cur) => (acc.unshift(cur), acc), []);
console.log(reverseArray([1,2,3]))