Oursky Developer Pre-Test Answer

answer1.js

/* Returns true if the 2nd array is a subset of 1st array. False otherwise.
*/

function isSubet (arr1, arr2) {
  return arr2.every(function (val) { 
    return arr1.indexOf(val) >= 0; 
  });
}

/* Example of how the above function works
*/
var x = ['A', 'B', 'C'];
var y = ['A', 'A', 'B', 'C'];
console.log(isSubet(x, y)); // true

answer2.md

O(n) because whole array will be searched; it is searched from front to back.

answer3.js

/* Write a function that takes an array of integers as input. For each integer, output the next
fibonacci number.
*/

var arr1 = [1,9,21];
for(i = 0; i < arr1.length; i++) {
	console.log(nextFibonacci(arr1[i]));
}
function nextFibonacci(num) {
  var fib = [];
  fib[0] = 0;
  fib[1] = 1;
  for (var i = 2; i <= num; i++) {
    fib[i] = fib[i - 1] + fib[i - 2];
    if (fib[i] > num) {
      return fib[i];
    }
  }
  if (fib[i - 1] < num) {
    return fib[i - 1] + num;
  }
  if (fib[i] = num - 1) {
    return fib[i - 1] + fib[i - 2];
  }
  if (fib[i - 1]) {
    return num + num;
  }
}

answer4.js

/* This code encountered a scoping issue. We can't use var because the i variable
   will be out of scope. There are two methods to solve the issue:
   1. use let
   2. use IIFE
*/

// Method 1 uses let
function createArrayOfFunctions(y) {
  var arr = [];
  for(let i = 0; i<y; i++) {
    arr[i] = function(x) { return x + i; };
  }
  return arr;
}

// Method 2 uses IIFE
function createArrayOfFunctions(y) {
  var arr = [];
  for(var i = 0; i<y; i++) {
    (function() {
      var _i = i;
      arr[_i] = function(x) { return x + i; };
    })();
  }
  return arr;
}