Solution.js

/**
 * @param {number[]} nums
 * @return {number}
 */
var removeDuplicates = function (nums) {
    let k = 0;
    for (const x of nums) {
        if (k === 0 || x !== nums[k - 1]) {
            nums[k++] = x;
        }
    }
    return k;
};