add_one_wizeline.js

/**
* This code is stored to save my exam to Wizeline that I took for fun, sorry Wizeline if someone finds this...
* Technically it could be pretty simple, a "join" of the array, then parse to int, then sum 1, then split again the numbers
* and parse each to integer, and that's it, but the rules are:
* the numbers are going to be between 1 and 9, no trailing zero...like: [1,2,3,4,5,6,7,8,9] in the array but...
* the array size can be up to 10,000 (10e4 -> 10 * 10 * 10 * 10) so we can have a digits.length of 10,000 which means, we can have
* a loooooooooooooot of numbers that are going to "sum" a really big number, if we use parseInt then, after the "join" we are going
* to end with a "32131e1221" which is something that we don't want to...
* and the "+1" rule so for example: [9,9,9] is converted to 999 + 1 = 1000 and we need to return [1,0,0,0] 
* 
* First as I already said, we don't want to use "parseInt" because it doesn't work for us, so we are going to use BigInt and 
* that's it...
*
* @param {array} digits The digits in a way like "[1,2,3]"
* @return {array} The new array with the "+1"
*/
function addOne(digits) {
  return (BigInt(digits.join('')) + BigInt(1)).toString().split('').map(el => parseInt(el, 10));
}

/**
* Simple tests:
*/
console.log(addOne([9,9,9])); // Returns [1,0,0,0]
console.log(addOne([1,2,3])); // Returns [1,2,4]

/**
* This function actually return random, so I don't know what value is going to return but...
* Uncomment the conditionals to test that if we add "9" at the end, the previous actually works!
*
* @return {array}
*/
function test() {
	/**
	* An array to create a random test
	* @type {array}
	*/
  const _test = [];
	
	/**
	* A "function" to generate random numbers between two...you can change this but well, you know, follow the rule
	* but I leave it with the chance to be modified so you can test it with whatever you want...
	* Just don't add "0" in min or negative numbers, and don't add 10 or more in the max...also, always min is lower
	* than max...so don't do something like "3,2" because well, I did this to test it fast ¬¬ don't complain...
	* 
	* @type {number} 
	* @param {number} min The min number (like 1...or 2)
	* @param {number} max The max number (like 8...or 9)
	* @return {number} A random value between "min" and "max" numbers
	*/
  const rand = (min, max) => Math.floor(Math.random() * (max - min) + min);
  for(let j = 1; j < 100; j++) {
    _test.push(rand(0,9));
  }
  return _test;
}

console.log(addOne(test())); // Returns ...don't know sorry :P