Remove K Digits

Problem statement

Given string num representing a non-negative integer num, and an integer k, return the smallest possible integer after removing k digits from num.

Example 1:

Input: num = "1432219", k = 3Output: "1219"Explanation: Remove the three digits 4, 3, and 2 to form the new number 1219 which is the smallest.

Example 2:

Input: num = "10200", k = 1Output: "200"Explanation: Remove the leading 1 and the number is 200. Note that the output must not contain leading zeroes.

Example 3:

Input: num = "10", k = 2Output: "0"Explanation: Remove all the digits from the number and it is left with nothing which is 0.

Constraints:

• 1 <= k <= num.length <= 105
• num consists of only digits.
• num does not have any leading zeros except for the zero itself.

My solution

/**
 * @param {string} num
 * @param {number} k
 * @return {string}
 */
var removeKdigits = function(nums, k) {
    const stack = []
    let removed = 0;
    for (const num of nums) {
        // console.log(">>>", stack, removed)
        while(stack.length > 0 && num < stack[stack.length - 1] && removed < k) {
            stack.pop();
            removed++;
        }
        stack.push(num)
    }
    
    while (removed < k) {
        stack.pop();
        removed++;
    }
    
    while (stack.length > 0 && stack[0] === "0") {
        stack.shift();
    }
    
    // console.log(stack)
    
    return stack.join("") || "0"
};