https://leetcode.com/problems/largest-number/

largestNumber.js

/**
 * @param {number[]} nums
 * @return {string}
 */
var largestNumber = function(nums) {
    
    const result = nums
    .map((num) => num.toString())
    .sort((a, b) => {
        const aBeforeB = parseInt(`${a}${b}`, 10);
        const bBeforeA = parseInt(`${b}${a}`, 10);
        return aBeforeB > bBeforeA ? -1 : 1;
    })
    .join('');
    
    return containsOnlyZeroes(result) ? '0' : result.replace(/^0+/, '');
};

function containsOnlyZeroes(str){
    for(let i=0; i<str.length; i++) if(str[i] !== '0') return false;
    return true;
}