/* eslint-disable */

const firstItem = (arr, cb) => {

cb(arr[0]);

// firstItem passes the first item of the given array to the callback function.

};

const getLength = (arr, cb) => {

cb(arr.length);

// getLength passes the length of the array into the callback.

};

const last = (arr, cb) => {

var last = arr[arr.length - 1]

cb(last);

// last passes the last item of the array into the callback.

};

const sumNums = (x, y, cb) => {

cb(x + y);

// sumNums adds two numbers (x, y) and passes the result to the callback.

};

const multiplyNums = (x, y, cb) => {

cb(x * y);

// multiplyNums multiplies two numbers and passes the result to the callback.

};

const contains = (item, list, cb) => {

for(let i= 0; i < list.length; i++){

if(item == list[i])

return cb(true);

}

return cb (false);

// contains checks if an item is present inside of the given array/list.

// Pass true to the callback if it is, otherwise pass false.

};

/* STRETCH PROBLEM */

const removeDuplicates = (array, cb) => {

// removeDuplicates removes all duplicate values from the given array.

// Pass the duplicate free array to the callback function.

// Do not mutate the original array.

var newarray = [];

for (var i = 0, l= array.length; i < l; i++)

if (newarray.indexOf(array[i]) === -1)

newarray.push (array[i]);

cb (newarray);

};

/* eslint-enable */

module.exports = {

firstItem,

getLength,

last,

sumNums,

multiplyNums,

contains,

removeDuplicates,

};