License Key Formatting

Problem statement

You are given a license key represented as a string s that consists of only alphanumeric characters and dashes. The string is separated into n + 1 groups by n dashes. You are also given an integer k.

We want to reformat the string s such that each group contains exactly k characters, except for the first group, which could be shorter than k but still must contain at least one character. Furthermore, there must be a dash inserted between two groups, and you should convert all lowercase letters to uppercase.

Return the reformatted license key.

Example 1:

Input: s = "5F3Z-2e-9-w", k = 4Output: "5F3Z-2E9W"Explanation: The string s has been split into two parts, each part has 4 characters.Note that the two extra dashes are not needed and can be removed.

Example 2:

Input: s = "2-5g-3-J", k = 2Output: "2-5G-3J"Explanation: The string s has been split into three parts, each part has 2 characters except the first part as it could be shorter as mentioned above.

Constraints:

• 1 <= s.length <= 105
• s consists of English letters, digits, and dashes '-'.
• 1 <= k <= 104

My solution

/**
 * @param {string} s
 * @param {number} k
 * @return {string}
 */
var licenseKeyFormatting = function(s, k) {
    let newS = s.replace(/-/g, "").toUpperCase()
    
    let right = newS.length - 1;
    let text = ""
    
    while (right >= 0) {
        
        const start = right - k + 1
        const stop = right + 1
        text = `${newS.slice(start < 0 ? 0 : start, stop)}${text === "" ? text : `-${text}`}`
        
        right -= k
    }
    
    return text
};