index.js

// Given an array nums and a value val, remove all instances of that value in -place and return the new length.
// Do not allocate extra space for another array, you must do this by modifying the input array in -place with O(1) extra memory.
// The order of elements can be changed.It doesn't matter what you leave beyond the new length.

// Example 1:
// Given nums = [3, 2, 2, 3], val = 3,
// Your function should return length = 2, with the first two elements of nums being 2.

// It doesn't matter what you leave beyond the returned length.
// Example 2:

// Given nums = [0, 1, 2, 2, 3, 0, 4, 2], val = 2,

// Your function should return length = 5, with the first five elements of nums containing 0, 1, 3, 0, and 4.
// Note that the order of those five elements can be arbitrary.
// It doesn't matter what values are set beyond the returned length.

// Solution

const removeElement = (nums, val) => {
    let count = 0;
    for (let i = 0; i < nums.length; i++) {
        if (nums[i] !== val) {
            nums[count++] = nums[i];
        }
    }

    nums.splice(count, nums.length - count)

    return nums.length;
};