JSFiddle - React, Tailwind, and code Playground

by Mark McFadden

JavaScript

var permArr = [],
  usedChars = [];

function permutes(input) {
  var i, ch;
  for (i = 0; i < input.length; i++) {
    ch = input.splice(i, 1)[0];
    usedChars.push(ch);
    if (input.length == 0) {
      permArr.push(usedChars.slice());
    }
    permutes(input);
    input.splice(i, 0, ch);
    usedChars.pop();
  }
  return permArr
};

var myArr = permutes([1,2,3]);
var currentNumber = 213;
var indexForNextNumber = 0;
for (i = 0; i < myArr.length; i++) {
    //console.log(myArr[i]);
    //console.log(Number(myArr[i].toString().replace(/,/g, '')));
   
    if(((i + 1) < myArr.length) && Number(myArr[i].toString().replace(/,/g, '')) == currentNumber){
        indexForNextNumber = (i + 1);
    }
};
//console.log(Number(myArr[indexForNextNumber].toString().replace(/,/g, '')));

var nextNumber = Number(myArr[indexForNextNumber].toString().replace(/,/g, ''))
if(nextNumber > currentNumber){
    console.log(nextNumber);
}