challenges-01.test.js

'use strict';

/* ------------------------------------------------------------------------------------------------
CHALLENGE 1

Write a function named greeting that takes in a string and returns the string in all uppercase letters.

Then, write a function named speaker that takes in a string and a callback function. The speaker function should return the string in all uppercase letters only by invoking the callback.
------------------------------------------------------------------------------------------------ */

const greeting = (word) => {
  return word.toUpperCase();
};

const speaker = (message, callback) => {
  return callback(message);
};

/* ------------------------------------------------------------------------------------------------
CHALLENGE 2

Write a function named addValues that takes in an array and a value and pushes the value into the array. This function does not need a return statement.

Then, write a function named addNumbers that takes in four arguments:
  - A number to be added to an array
  - An array into which the number should be added
  - The number of times the number should be added
  - A callback function to use to add the numbers to the array (Hint: you already defined it)

Within the addNumbers function, invoke the callback function as many times as necessary, based on the third argument of the addNumbers function.

Return the modified array.
------------------------------------------------------------------------------------------------ */

const addValues = (arr, value) => arr.push(value);

const addNumbers = (num, arr, times, callback) => {
  for (let i = 0; i < times; i++) callback(arr, num);
  return arr;
};

/* ------------------------------------------------------------------------------------------------
CHALLENGE 3

Write a function named removeOne that takes in a number and an array. If the number divided by three has a remainder of two, pop one element off of the array.

Hint: you may want to look into the modulo operation.

Then, write a function named removeElements that takes in an array and a callback. This function should use a for loop to iterate over the array and invoke the callback once for each element in the array.

Return the modified array.
------------------------------------------------------------------------------------------------ */

const removeOne = (num, arr) => {
  if (num % 3 === 2) arr.pop();
};

const removeElements = (arr, callback) => {
  for (let i = 0; i < arr.length; i++) {
    callback(arr[i], arr);
  }
  return arr;
};

/* ------------------------------------------------------------------------------------------------
CHALLENGE 4

Write a function named removeWithForEach that produces the same output as challenge 3, but uses forEach.
------------------------------------------------------------------------------------------------ */

const removeWithForEach = (arr, callback) => {
  arr.forEach((value) => callback(value, arr));
  return arr;
};

/* ------------------------------------------------------------------------------------------------
CHALLENGE 5

Write a function named removeWithAnon that produces the same output as challenges 3 and 4.

This function should use forEach again, but rather than taking in a callback as an argument, define an anonymous function as the argument to forEach.

This anonymous function should accept up to three arguments: the element, the index, and the array.
------------------------------------------------------------------------------------------------ */

const removeWithAnon = (arr) => {
  arr.forEach((value) => {
    if (value % 3 === 2) arr.pop();
  });
  return arr;
};

/* ------------------------------------------------------------------------------------------------
CHALLENGE 6

Write a function named createList that takes in an array of the current store intentory.

The inventory is formatted like this:
[
  { name: 'apples', available: true },
  { name: 'pears', available: true },
  { name: 'oranges', available: false },
  { name: 'bananas', available: true },
  { name: 'blueberries', available: false }
]

This function should use forEach to populate your grocery list based on the store's inventory. If the item is available, add it to your list. Return the final list.
------------------------------------------------------------------------------------------------ */

const createList = (availableItems) => {
  let list = [];
  availableItems.forEach((element) => {
    if (element.available) list.push(element.name);
  });
  return list;
};

/* ------------------------------------------------------------------------------------------------
CHALLENGE 7

Write a function named fizzbuzz that takes in an array of numbers.

Iterate over the array using forEach to determine the output based on several rules:
  - If a number is divisible by 3, add the word "Fizz" to the output array.
  - If the number is divisible by 5, add the word "Buzz" to the output array.
  - If the number is divisible by both 3 and 5, add the phrase "Fizz Buzz" to the output array.
  - Otherwise, add the number to the output array.

Return the resulting output array.
------------------------------------------------------------------------------------------------ */

const fizzbuzz = (arr) => {
  let outputArray = [];
  arr.forEach((element) => {
    let three = element % 3 === 0;
    let five = element % 5 === 0;
    if (three && five) {
      outputArray.push('Fizz Buzz');
    } else if (three) {
      outputArray.push('Fizz');
    } else if (five) {
      outputArray.push('Buzz');
    } else {
      outputArray.push(element);
    }
  });
  return outputArray;
};

/* ------------------------------------------------------------------------------------------------
TESTS

All the code below will verify that your functions are working to solve the challenges.

DO NOT CHANGE any of the below code.

Run your tests from the console: jest challenges-01.test.js

------------------------------------------------------------------------------------------------ */

describe('Testing challenge 1', () => {
  test('It should return the message with all uppercase characters', () => {
    expect(speaker('hello 301 students!', greeting)).toStrictEqual('HELLO 301 STUDENTS!');
  });
});

describe('Testing challenge 2', () => {
  test('It should add the number 8 to the array five times', () => {
    expect(addNumbers(8, [], 5, addValues)).toStrictEqual([8, 8, 8, 8, 8]);
    expect(addNumbers(8, [], 5, addValues).length).toStrictEqual(5);
  });
});

describe('Testing challenge 3', () => {
  test('It should remove three elements from the array', () => {
    expect(removeElements([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], removeOne)).toStrictEqual([1, 2, 3, 4, 5, 6, 7]);
    expect(removeElements([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], removeOne).length).toStrictEqual(7);
  });
});

describe('Testing challenge 4', () => {
  test('It should remove three elements from the array', () => {
    expect(removeWithForEach([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], removeOne)).toStrictEqual([1, 2, 3, 4, 5, 6, 7]);
    expect(removeWithForEach([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], removeOne).length).toStrictEqual(7);
  });
});

describe('Testing challenge 5', () => {
  test('It should remove three elements from the array', () => {
    expect(removeWithAnon([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])).toStrictEqual([1, 2, 3, 4, 5, 6, 7]);
    expect(removeWithAnon([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]).length).toStrictEqual(7);
  });
});

describe('Testing challenge 6', () => {
  const inventory = [
    { name: 'apples', available: true },
    { name: 'pears', available: true },
    { name: 'oranges', available: false },
    { name: 'bananas', available: true },
    { name: 'blueberries', available: false },
  ];

  test('It should only add the available items to the list', () => {
    expect(createList(inventory)).toStrictEqual(['apples', 'pears', 'bananas']);
    expect(createList(inventory).length).toStrictEqual(3);
  });
});

describe('Testing challenge 7', () => {
  const inputs = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16];

  test('It should print out messages or numbers', () => {
    expect(fizzbuzz(inputs)).toStrictEqual([
      1,
      2,
      'Fizz',
      4,
      'Buzz',
      'Fizz',
      7,
      8,
      'Fizz',
      'Buzz',
      11,
      'Fizz',
      13,
      14,
      'Fizz Buzz',
      16,
    ]);
    expect(fizzbuzz(inputs).length).toStrictEqual(16);
  });
});