freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/stand-in-line.md

id, title, challengeType, videoUrl, forumTopicId, dashedName

id	title	challengeType	videoUrl	forumTopicId	dashedName
56533eb9ac21ba0edf2244c6	Stand in Line	1	https://scrimba.com/c/ca8Q8tP	18307	stand-in-line

--description--

In Computer Science a queue is an abstract Data Structure where items are kept in order. New items can be added at the back of the queue and old items are taken off from the front of the queue.

Write a function nextInLine which takes an array (arr) and a number (item) as arguments.

Add the number to the end of the array, then remove the first element of the array.

The nextInLine function should then return the element that was removed.

--hints--

nextInLine([], 5) should return a number.

assert.isNumber(nextInLine([], 5));

nextInLine([], 1) should return 1

assert(nextInLine([], 1) === 1);

nextInLine([2], 1) should return 2

assert(nextInLine([2], 1) === 2);

nextInLine([5,6,7,8,9], 1) should return 5

assert(nextInLine([5, 6, 7, 8, 9], 1) === 5);

After nextInLine(testArr, 10), testArr[4] should be 10

nextInLine(testArr, 10);
assert(testArr[4] === 10);

--seed--

--before-user-code--

var logOutput = [];
var originalConsole = console
function capture() {
    var nativeLog = console.log;
    console.log = function (message) {
        logOutput.push(message);
        if(nativeLog.apply) {
          nativeLog.apply(originalConsole, arguments);
        } else {
          var nativeMsg = Array.prototype.slice.apply(arguments).join(' ');
          nativeLog(nativeMsg);
        }
    };
}

function uncapture() {
  console.log = originalConsole.log;
}

capture();

--after-user-code--

uncapture();
testArr = [1,2,3,4,5];
(function() { return logOutput.join("\n");})();

--seed-contents--

function nextInLine(arr, item) {
  // Only change code below this line
  
  return item;
  // Only change code above this line
}

// Setup
const testArr = [1, 2, 3, 4, 5];

// Display code
console.log("Before: " + JSON.stringify(testArr));
console.log(nextInLine(testArr, 6));
console.log("After: " + JSON.stringify(testArr));

--solutions--

const testArr = [1, 2, 3, 4, 5];

function nextInLine(arr, item) {
    arr.push(item);
    return arr.shift();
}