Remove All Instances from an Element from an Array in Place and Return Length

remove-element-array-in-place.js

/**
 * @param {number[]} nums
 * @param {number} val
 * @return {number}
 */
var removeElement = function(nums, val) {
    
    let slow=0;
    
    for(let fast = 0; fast < nums.length; fast++) {
        if(nums[fast]!==val) {
            nums[slow] = nums[fast];
            slow++
        }
    }
    
    return slow;
    
};