nextBiggerNumber.js

// Link to kata: https://www.codewars.com/kata/55983863da40caa2c900004e

function nextBigger(n){
    var d = n.toString().split('');
    
    // find the pivot, the point (from right) where i > i-1
    var p = -1;
    for (var i = d.length-1; i > 0; i--) {
      if (+d[i] > +d[i-1]) {
        p = i-1;
        break;
      }
    }
    
    // if we are unable to find the pivot, skip
    if (p == -1) return p;
      
    // splice the digits in the pivot
    var right = d.splice(p);
    
    // extract pivot
    var pv = right.splice(0, 1)[0];
    
    // find the lowest number > pv
    var mm = null, mmi = null;
    for (var i = 0; i < right.length; i++) {
      if (right[i] > pv) {
        if (mm == null || right[i] < mm) {
          mm = right[i];
          mmi = i;
        }
      }
    }
  
    if (mmi == null) return -1;
    
    right.splice(mmi, 1);
    right.push(pv);
    right = right.sort();
    
    // concat the left + new pivot + right part
    var ret = +d.concat([mm]).concat(right).join('');
    if (ret < n) return -1;
    
    return ret;
  }