JSFiddle - React, Tailwind, and code Playground

by Mukesh Yadav

JavaScript

var numbers = [3, 4, -1, 1];
//var numbers = [-1, 1, 3, 4];
//numbers = [1, 2, 0];

numbers.sort(function(a, b) {
  if (a > b) {
    return 1;
  }
  if (a < b) {
    return -1;
  }
  return 0;
});

console.log(numbers);

function missingNumber(numbers) {
  var nextNumber = numbers[0];
  for (var i = nextNumber; i <= numbers.length; i++) {
    if (nextNumber > 0 && numbers[i] !== nextNumber) {
      break;
    }
    nextNumber++;
  }
  return nextNumber;
}


/*function missingNumber(numbers) {
	var nextNumber = (numbers[0] + 1);
  for (var i = 1; i < numbers.length; i++) {
    if (nextNumber > 0 && numbers[i] !== nextNumber) {
      return nextNumber;
    }else if(nextNumber < 1){
    	i--;
    }
    nextNumber++;
  }
  return nextNumber;
}*/

console.log(missingNumber(numbers));