excercises.md

Excercise 1

• Write a function filterArray that takes an array of values and a callback function as arguments.

• The filterArray function should use the callback function to filter the array and return a new array with only the elements that pass the filter.

• The callback function should take a single argument (an array element) and return true or false depending on whether the element should be included in the filtered array.

const myArray = [1, 2, 3, 4, 5, 6];

function isEven(num) {
  return num % 2 === 0;
}

const filteredArray = filterArray(myArray, isEven);

console.log(filteredArray); // [2, 4, 6]

Excercise 2

• Write a function doubleArray that takes an array of numbers as an argument and returns a new array where each element is twice the value of the corresponding element in the original array.

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

function doubleNum(num) {
  return num * 2;
}

const doubledArray = doubleArray(myArray, doubleNum);

console.log(doubledArray); // [2, 4, 6, 8, 10]

Excercise 3

• Write a function sumArray that takes an array of numbers as an argument and returns the sum of all the elements in the array.

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

function sum(acc, num) {
  return acc + num;
}

const sumOfArray = sumArray(myArray, sum);

console.log(sumOfArray); // 15

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Excercise 4

const users = [
  { id: 1, firstName: "John", lastName: "Doe" },
  { id: 2, firstName: "Jane", lastName: "Smith" },
  { id: 3, firstName: "Jack", lastName: "Jill" },
  { id: 4, firstName: "James", lastName: "Bond" },
  { id: 5, firstName: "Jane", lastName: "Doe" },
  { id: 6, firstName: "John", lastName: "Smith" },
  { id: 7, firstName: "Jack", lastName: "Jill" },
  { id: 8, firstName: "James", lastName: "Bond" },
  { id: 9, firstName: "Jane", lastName: "Doe" },
  { id: 10, firstName: "John", lastName: "Smith" },
  { id: 11, firstName: "Jack", lastName: "Jill" },
  { id: 12, firstName: "James", lastName: "Bond" },
  { id: 13, firstName: "Jane", lastName: "Doe" },
  { id: 14, firstName: "John", lastName: "Smith" },
  { id: 15, firstName: "Jack", lastName: "Jill" },
  { id: 16, firstName: "James", lastName: "Bond" },
  { id: 17, firstName: "Jane", lastName: "Doe" },
  { id: 18, firstName: "John", lastName: "Smith" },
  { id: 19, firstName: "Jack", lastName: "Jill" },
  { id: 20, firstName: "James", lastName: "Bond" },
  { id: 21, firstName: "Jane", lastName: "Doe" },
  { id: 22, firstName: "John", lastName: "Smith" },
  { id: 23, firstName: "Jack", lastName: "Jill" },
  { id: 24, firstName: "James", lastName: "Bond" },
  { id: 25, firstName: "Jane", lastName: "Doe" },
  { id: 26, firstName: "John", lastName: "Smith" },
  { id: 27, firstName: "Jack", lastName: "Jill" },
  { id: 28, firstName: "James", lastName: "Bond" },
  { id: 29, firstName: "Jane", lastName: "Doe" },
];

• Create a function called getUsersWithFullName that takes an array of users and returns an array of users with id, firstName, lastNam and fullName without using the map function

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Excercise 5

• Create a function called getUserWithId to take an array of users and id and return the user with the given id.

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Excercise 6

• create a function called getUsersFirstNameStartsWith to take an array of users and a charachter and return new array of users with the first name starts with the given charachter.